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Chapter 4. Shipbuilding 101: The Making ... > Box Modeling from a Background Image

Box Modeling from a Background Image

The boat you will be re-creating is the USS Agamenticus, an ironclad warship built in Portsmouth, New Hampshire, in 1865. You can find photos, more information, and links about the Agamenticus and similar ships at http://www.history.navy.mil/photos/sh-usn/usnsh-a/agament.htm, a public web site of the Department of the Navy. Figure 4.3 shows the completed 3ds max 6 model.

Figure 4.3. An example of the model of the USS Agamenticus that you will be building in this chapter.


This boat will not be historically or physically accurate, but you will learn a modeling process that you can apply to many different objects from boats, planes, or furniture, to more organic objects such as characters.

The background image you use as a guide to the modeling is a set of hull plans from a similar class of boat, although not of the USS Agamenticus itself. The boat is long enough so that the plans are broken into the bow and stern lines with the connecting hull section to be interpolated as a straight line.

note

The bow is the front of the boat, the stern is the back of the boat, and the keel is the main structural element that runs the length of the bottom of the boat.


The boat plans are typical hull plans consisting of vertical station lines and horizontal water lines. You will edit a box to match the curvature defined by the intersections of these lines, real or interpolated, to form the shape of the hull. If you are not familiar with hull design, work slowly at first, making sure you understand why you are moving entities of the box, not just moving them because it is written in the steps.

I've created boat hulls through various modeling techniques such as lofting, spline and patch techniques, and NURBS modeling, and none has proven so fast and efficient as Box modeling (as it will be for you, after you learn to read the hull design plans).

This chapter is a good one in which to practice using the Hold and Fetch commands found in the Edit pull-down menu, as well as the Save keyboard shortcut of Ctrl+S. These options enable you to go back if you mess up during the process.

Background Images and Box Modeling Techniques

You first learn to set up a scene with background images in the various viewports and trace those images by editing an editable poly object at sub-object levels. The bow section and stern section are built separately in the scene, and are then attached later in this chapter.

Exercise 4.1 Configuring for Background Images in Viewports

1.
Open the file called Ch04_BoatHull01.max on the CD-ROM. From the File pull-down menu, choose Save As, point to an appropriate subdirectory on your hard drive, and use the plus sign button to save a new file with the name incremented to Ch04_BoatHull02.max. There is nothing in this scene, but it ensures that you are using correct units and viewport settings.

2.
In the Views pull-down menu, choose Viewport Background (Alt+B). In the Viewport Background dialog, click the Files button and, from the CD-ROM, open Hull_plan.jpg. In the Aspect Ratio area, check the Match Bitmap radio button and make sure that Lock Zoom/Pan is checked. For the Apply Source and Display To area, check the All Views radio button (see Figure 4.4). Matching the bitmap aspect ratio is important to keep the image from distorting when it tries to fit different viewport layouts. Lock Zoom/Pan enable you to zoom and pan while the image retains its relative size. Apply to All Views causes the image to show in each viewport. Click OK.

Figure 4.4. In the Viewport Background dialog, check Match Bitmap, Lock Zoom/Pan, and All Views options for this exercise.


3.
Right-click the viewport label of each ortho viewport, Top, Front, Left, and clear the Show Grid option. Then, right-click the Perspective viewport label and clear both Show Grid and Show Background. You will use a clean Perspective viewport to keep track of the modeling progress. Then, set each viewport to use Smooth + Highlights shading (see Figure 4.5). The menu closes each time you change an option, so you must right-click the viewport label each time.

Figure 4.5. Right-click the viewport labels of the ortho viewports, Top, Front, and Left, and clear the Show Grid options. Right-click the Perspective viewport label and clear Show Grid and Show Background.


tip

This is a good point at which to use the keyboard shortcut Ctrl+S to save the file with the current name (and to use the Edit pull-down menu, Hold option for added safety).

4.
Right-click the Perspective label and choose Configure in the menu. In the Viewport Configuration dialog, check the Rendering Options feature called Display Selected with Edged Faces (see Figure 4.6). Click OK. This action causes objects selected in shaded viewports to automatically show both the shaded faces and the wireframe edges, making sub-object editing much easier.

Figure 4.6. Right-click the Perspective viewport label and choose Configure. In the dialog, check the option called Display Selected with Edged Faces for simultaneous shaded and wireframe views of only the selected objects.


caution

Using background images in viewports often can use large amounts of memory when trying to zoom or pan in the viewports. You will see warning dialogs asking if you want to continue. Turning off the viewport Show Background image for the zoom or pan operation, and then turning it back on again, keeps the warning dialog from slowing the process.

5.
Activate the Top viewport and use Zoom and Pan to center the bow plan in the viewport (see Figure 4.7).

Figure 4.7. In the Top viewport, use Zoom and Pan to roughly center the bow plan in the viewport.


6.
In the Create panel, Geometry panel, click the Box button in the Object Type rollout and drag a box to cover the bow plan drawing. In the Modify panel, Parameters rollout, set the Length to 4' 8", the Width to 12'4" and the Height to 3'0". Rename the object Bow01.

tip

The options you set in the Viewport Configuration dialog pertain to all viewports, only the active viewport, or all but the active viewport, depending on the option checked in the Apply To area of the Viewport Configuration dialog.

7.
You cannot see the plan below the box to make sure the alignment is close. Right-click the box and choose Properties in the Quad menu. In the Object Properties dialog, Display Properties area, check the See Through option (see Figure 4.8). Click OK.

Figure 4.8. Right-click the box in the Top viewport and choose Properties in the Quad menu. Check the See-Through option in the Display Properties area.


8.
On the main toolbar, click the Select and Move button and, in the Top viewport, move the box to align it with the bow plan as best you can, remembering that accuracy is not so important in this exercise (see Figure 4.9).

Figure 4.9. Using the Select and Move tool from the main toolbar, you can easily position the semitransparent box in the Top viewport over the bow plan.


9.
Right-click the box again and choose Convert To and Convert to Editable Poly from the cascading menu (see Figure 4.10). In the Modify panel, rename the box Bow01.

Figure 4.10. Right-click the box to Convert to Editable Poly from the cascading menu.


10.
Save the file; it should already be named Ch04_BoatHull02.max.

By loading a background image in each of the ortho viewports and setting it to respect the original aspect ratio of the image, you can position objects quite accurately over the background with ease. The ability to change the properties of an object to See-Through helps this process.

Slicing Station Lines

In Exercise 4.2, you slice the Bow01 box at each station line, lines that run vertically through the hull, in the Top viewport. A tool called Quick Slice enables you to quickly slice through the object to create new vertices and edges that will define new polygons in the object. These can then be further edited to form the bow of the hull.

note

The background image is undoubtedly scanned from old paper drawings, leaving something to be desired in the quality. Follow the steps carefully and interpolate where it looks like a line might be, even if you cannot clearly see it.

You should also use Edit, Hold after each slice in case something goes wrong and you need to get back to a point where you know the model is correct.


Exercise 4.2 Modifying an Editable Poly to Slice at Station Lines

1.
Open the file called Ch04_BoatHull02.max on the CD-ROM or from the preceding exercise. From the File pull-down menu, choose Save As, point to an appropriate subdirectory on your hard drive, and use the plus sign button to save a new file with the name incremented to Ch04_BoatHull03.max.

note

You might have to turn on Display Selected with Edged Faces for this viewport to see the results of the following steps. It is already active in Perspective viewport, depending on the options you set in Exercise 4.1, step 4.

2.
You can use Figure 4.11 as a reference for where the seven slices will be taken; there are two slices on the right side for the keel and stem of the boat.

Figure 4.11. The black triangles indicate where the station lines are in the plan. Notice that there are two triangles on the right side to create a stem and keel slice.


3.
Right-click in the Top viewport to activate it and click the Min/Max Toggle (Alt+W) at the lower right of the display to maximize the Top viewport. Make sure Bow01 is selected. In the Modify panel, Stack View, expand Editable Poly and highlight Edge sub-object level. In the Edit Geometry rollout, click the QuickSlice button (see Figure 4.12).

Figure 4.12. When in sub-object Edge mode, click QuickSlice in the Modify panel, Edit Geometry rollout.


4.
In the Top viewport, pick Bow01 on the lower edge where it intersects with the first station line. Move the mouse and you see a red slice line through the box. Move the cursor over the station line near the top to ensure a vertical slice, and click to finalize the step (see Figure 4.13). If the slice was successful, click the Hold option in the Edit pull-down menu.

Figure 4.13. Use the QuickSlice command to slice from the bottom edge of the box in the Top viewport where it meets the first station line. Then, move the cursor along the station line and click when the new red slice line is vertical.


5.
Repeat step 4 for each of the other six station lines, creating two near the right edge to form the stem and keel. Remember to use Edit, Hold after each Quick Slice in case something goes wrong so that you can use Fetch to return to the last good action. The box should look like Figure 4.14.

Figure 4.14. Use QuickSlice to create a total of seven new station lines in Bow01.


6.
In the Modifier panel, Stack view, highlight Editable Poly to exit sub-object mode. Save the file. It should already be named Ch04_BoatHull03.max.

warning

The QuickSlice plane is always perpendicular to your line of sight in the viewport. For this reason, it is dangerous to use QuickSlice in a nonorthographic viewport unless you are absolutely sure of what you are doing.


The editable poly QuickSlice command provides a great way to slice new edges and vertices in a 3D object.

Moving Vertices to Form the Hull Shape

In Exercise 4.3, you learn to move selection sets of vertices to make Bow01 match the curve of the hull plan as seen from the top. You learn about Ignore Backfacing, a command that is helpful in the following exercises.

Exercise 4.3 Ignore Backfacing and Vertex Editing

1.
Open the file called Ch04_BoatHull03.max on the CD-ROM or from the preceding exercise. From the File pull-down menu, choose Save As, point to an appropriate subdirectory on your hard drive, and use the plus sign button to save a new file with the name incremented to Ch04_BoatHull04.max.

2.
Select Bow01 in the Top viewport. In the Modify panel, Stack view, highlight the Vertex sub-object level. The vertices of the new slice edges highlight red in the viewports. Make sure Select Object is highlighted on the main toolbar and click anyplace in the Top viewport to deselect all vertices. The vertices are now blue. In the Modify panel, Selection rollout, be sure that the Ignore Backfacing option check box is clear (see Figure 4.15). As seen in the Top viewport, each blue tick represents two vertices, one at the upper and another at the lower edge. If Ignore Backfacing is checked, it is impossible to select the lower vertex and the editing will not be correct. You will need to check the option in later exercises.

Figure 4.15. Make sure that the Ignore Backfacing check box is clear so that you can select vertices on the back side of the box as seen in the Top viewport.


3.
On the main toolbar, click the Select and Move button. In the Top viewport, drag a selection window on the vertices second from the left, top edge (see Figure 4.16).

Figure 4.16. While in Select and Move mode, drag a selection window to select the two vertices in this area.


4.
Move the cursor over the Y-axis restrict arrow of the Transform gizmo and move the two vertices downward until they meet the curved edge of the drawing (see Figure 4.17).

Figure 4.17. Move the pair of vertices in the negative Y-axis to meet the curve of the plan.


caution

Just picking the two vertices will be impossible, because one is directly above the other. You must use a window selection area with Ignore Backfacing off to select them.

5.
Repeat step 4 for each pair of vertices along the upper edge in the Top viewport. Zoom in on the Top viewport to see what you are doing, but do not be obsessive about accuracy. The last two pairs should match the stem in the drawing (see Figure 4.18).

Figure 4.18. Move each pair of vertices to match the curve of the hull plan. Watch that you match the stem on the right.


6.
In the Modify panel, Stack view, highlight Editable Poly to exit sub-object mode. Save the file; it should already be called Ch04_BoatHull04.max.

Slicing the Water Lines

Exercise 4.4 is similar to Exercise 4.2 and gives you more practice with QuickSlice. However, you learn to switch viewports and align the model with another view of the plans. Remember that this is a 3D model, so working in one view is highly impractical. You should always work in the viewport that gives you the most control over your modeling. This is another reason to learn your reference coordinate systems well, because the directions of the X, Y, and Z axes can change in each viewport and coordinate system combination.

Exercise 4.4 Slicing the Horizontal Water Lines

1.
Open the file called Ch04_BoatHull04.max on the CD-ROM or from the preceding exercise. From the File pull-down menu, choose Save As, point to an appropriate subdirectory on your hard drive, and use the plus sign button to save a new file with the name incremented to Ch04_BoatHull05.max.

2.
Activate the Front viewport by right-clicking in it, and then zoom and pan to view the side drawing of the boat's bow section. You first align and resize the Bow01 to fit the plan.

3.
In the Front viewport, select Bow01 and, on the main toolbar, click Select and Move. Move Bow01 in the X and Y axes to align the right and bottom edges to the drawing. In the Modify panel, Stack view, highlight level. Drag a selection window around pairs of vertices in the top row and, using the Y-axis restrict arrow of the Transform gizmo, move the vertices to match to top of the drawing (see Figure 4.19).

Figure 4.19. Match the bottom and right edges of Bow01 to the plan and, at Vertex sub-object level, move pairs of vertices in the top row to match the plan.


tip

Whether you zoom with the Zoom button at the lower right of the display or you use the mouse wheel, holding the Ctrl key increases the zoom factor and speed, and holding the Alt key diminishes the effects, offering more control.

4.
Right-click the Front viewport label and make sure the Edged Faces option is checked in the menu. This enables you to see the edges and shaded object simultaneously. In the Modify panel, Stack view, highlight Edge sub-object level. In the Edit Geometry rollout, click the QuickSlice button. In the Front viewport, use QuickSlice to cut six horizontal water lines as indicated by the black arrows in Figure 4.19. Click the left edge of Bow01 first, and then move the cursor to the right along the drawing line to create a horizontal slice along each water line or parallel to them. Use Edit, Hold after each slice so that you have a way to back up, other than Undo, if you make a mistake. Pick the QuickSlice button to disable it when you finish all six slices. The final slice pattern for station lines and water lines should look like what's shown in Figure 4.20.

Figure 4.20. You have now used QuickSlice to create vertical station lines and horizontal water lines in Bow01.


note

The second new slice from the top does not fall on a water line in the drawing. It is perfectly acceptable to interpolate between water lines to give more points to describe a smooth hull if you think it is necessary. Keep in mind, however, that efficiency is of prime importance in modeling, and the detail must justify the extra overhead.

5.
In the Modify, Stack view, highlight Editable Poly to exit sub-object mode. Save the file; it should already be named Ch04_BoatHull05.max.

Forming the Hull Curvature

In Exercise 4.5, you learn to edit at Vertex level to move the vertices at the intersection of station lines and water lines to match the curvature of the hull as described in the end drawings of the boat. First, you rotate Bow01 in the Top viewport and then, in the Front viewport, align it with the drawing as viewed from the bow. You then learn to select single vertices and move them into place without affecting vertices in the background that need to stay in place. Make sure you review the steps first to have a clear understanding of what this will accomplish and why you must pick vertices carefully. You then move pairs of vertices to form the curve of the bow.

note

As mentioned at the beginning of this chapter, the boat plans used here do not represent the full length of the boat. The bow and stern sections are depicting the areas of maximum curvature and the midsection of the boat is presumed to be a fairly straight-line interpolation. The end-view drawings represent the boat looking both forward and aft with the outer edges being the widest point of the hull. Therefore, Bow01 does not match the width of the hull drawing as seen from the front, so it will be the centerline you will use as the matching edge.


Exercise 4.5 Moving Vertices at the Intersection of Station Line and Water Line to Fit the Hull Curvature

1.
Open the file called Ch04_BoatHull05.max on the CD-ROM or from the preceding exercise. From the File pull-down menu, choose Save As, point to an appropriate subdirectory on your hard drive, and use the plus sign button to save a new file with the name incremented to Ch04_BoatHull06.max.

note

Again, you might have to turn on Display Selected with Edged Faces for this viewport to see the results of the following steps. It is already active in Perspective viewport, depending on the options you set in Exercise 4.1, step 4.

2.
Click the Select Object button on the main toolbar and, in the Top viewport, select Bow01. You must first rotate it so that it matches up with the end view of the hull in the Front viewport. On the main toolbar, click the Angle Snap toggle, and then right-click Angle Snap to see that it is set to 5 degrees. Click the Select and Rotate button on the main toolbar (see Figure 4.21). Close the Grid and Snap Settings dialog.

Figure 4.21. Click, and then right-click the Angle Snap toggle on the main toolbar. You see that the default angle is 5 degrees. Close the Grid and Snap Settings dialog and click the Select and Rotate button on the main toolbar.


3.
In the Top viewport, rotate Bow01 in the Z-axis –90 degrees. Rotate will be snapping in 5-degree increments, and you can read the angle in the Transform Type-In fields at the bottom center of the display. The point of the bow faces downward, as shown in Figure 4.22.

Figure 4.22. Using Angle Snap, you can rotate Bow01 in the Top viewport in 5-degree increments. Read the angle in the Transform Type-In fields until it is rotated–90 degrees. The bow will point downward.


note

You might want to right-click on the Top viewport label and clear Show Background to make this faster.

4.
Right-click in the Front viewport to activate it. On the main toolbar, click Select and Move and move Bow01 to match the center of the end drawing. The right side of the drawing is looking from the bow toward the stern. The left side is looking from the stern forward. Match the bottom of Bow01 to the very bottom of the keel projection (see Figure 4.23).

Figure 4.23. In the Front viewport, move Bow01 to match the left edge to the enter of the end view and the bottom edge to the bottom of the keel.


5.
Now, move pairs of vertices in the Front viewport to form the keel of the boat. Zoom in to the bow area in the Top and Perspective viewports to see the curved side of the boat, and zoom in close in the Front viewport to see the whole Bow01 (see Figure 4.24). Edit, Hold at this point.

Figure 4.24. In the Top viewport, zoom close to the bow; in the Front viewport, zoom to view Bow01; in the Perspective viewport, Arc Rotate and zoom to see the curved side of the boat.


caution

You are about to move vertices in a very specific manner. It would be wise to use the Edit, Hold option frequently.

6.
In the Modify panel, Stack view, highlight Vertex sub-object mode. Make sure the Ignore Backfacing check box is clear in the Selection rollout. In the Front viewport, click carefully in empty space to deselect all vertices, and then drag a window around the third pair of vertices from the bottom left of Bow01. You should see two vertices selected at the bottom of the Selection rollout of the Modify panel (see Figure 4.25).

Figure 4.25. Drag a selection window around the pair of vertices third from the bottom left in the Front viewport.


7.
In the Front viewport, move the pair of selected vertices left (negative X-axis; use the Transform gizmo) until they are behind the second pair from the left. This defines the width of the keel. Continue from left to right until you have moved all the pairs to build a straight keel (see Figure 4.26). You can Arc Rotate in the Perspective viewport to see the keel clearly.

Figure 4.26. Move the pair of selected vertices in the negative X-axis behind the second pair from the left. Repeat this for each pair to the right to form a keel.


8.
Now, move individual vertices so they follow the curvature lines of the drawing in the Front viewport. They do not have to be on the curve lines, but you use those as a guide. The top two rows of vertices and the left two columns of vertices do not get moved because they form the gunwales and keel of the boat. To avoid vertices that might be behind the model as you view it in the Front viewport, check the Ignore Backfacing check box in the Selection rollout of the Modify panel. Start with the fourth column from the left and move the four vertices from the bottom, one at a time, in the negative X-axis, to match the curve nearest that column (see Figure 4.27).

Figure 4.27. Move the four bottom vertices of the forth column from the left to match the drawing curve nearest to it. You do not need to be on the curve; just keep the line parallel.


9.
Working from left to right, move the subsequent vertices in the negative X-axis to match their closest curve in the drawing. Bow01 should take on the shape of the hull, as shown in Figure 4.28. Use Edit, Hold often so that you can use Edit, Fetch to recover from any mistakes. The first time you do this, it might seem complex, but when you understand the process, you will be able to perform it quickly.

Figure 4.28. Move the bottom four vertices of the other columns to match the curvature of their corresponding curve in the drawing.


10.
Now, clean up the curvature of the bow from the side view. Click Editable Poly in the Stack view to exit sub-object mode and, in the Left viewport, move Bow01 to match the right edge and bottom of the side drawing and zoom in on the lower-right corner (see Figure 4.29).

Figure 4.29. In the Left viewport, move Bow01 to align the right and bottom edge to the drawing and zoom in.


11.
In the Modify panel, Stack view, highlight Vertex. In the Selection rollout, clear the Ignore Backfacing check box. In the Left viewport, select pairs of vertices at the intersections near the bottom right of the bow and move them in the negative X-axis to follow the curvature of the drawing. You need to select by window to get the two vertices, front and back, at each intersection. You have 14 pairs to move (see Figure 4.30).

Figure 4.30. Move 14 pairs of vertices in the negative X-axis to match the curvature of the drawing at the lower right of the bow in the Left viewport.


12.
Highlight Editable Poly in the Stack view to exit sub-object mode. Save the file; it should already be called Ch04_BoatHull06.max.

Resizing and Positioning the Bow and Stern to Full Scale

In Exercise 4.6, you open a new file that has the stern section modeled in the same way as Bow01, and both have been rotated and aligned to match the center edges and bottoms and to butt them together. Although the drawing was matched closely for the creation of the two objects, no scale relates the parts to the drawing. The determination has been made that scaling both objects by 500 percent closely represents the true size of the boat.

tip

You don't have to make everything in real-world sizes in 3ds max, but it is prudent to do so, especially with collaborative work. If your boat is only a few inches long, it will still look correct until you match it to someone else's scene that is in real units.


Exercise 4.6 Scaling and Positioning the Boat Sections

1.
Open Ch04_Boat01.max from the CD-ROM. This file has the stern section, so do not use the file from the preceding exercise. Save the file to your hard drive with the name Ch04_Boat02.max. The file has a bow and stern section and the background image has been turned off (see Figure 4.31).

Figure 4.31. The bow and stern sections of the boat with Show Background turned off.


2.
You now scale the bow and stern sections by 500 percent to make them close to real-world sizes. You learned in the preceding chapter that you should never scale objects in 3ds max because of the modifier stack evaluation order. Always apply an XForm modifier to the object and scale the modifier. In the Perspective viewport, select Bow01. In the Modify panel, Modifier List, choose XForm. On the main toolbar, click the Select and Uniform Scale button. In the status bar, toggle from Absolute Mode Transform Type-In to Offset Mode Transform Type-In and enter 500 in the X: numeric field—the only one available in Uniform Scale, it scales in all axes (see Figure 4.32). Press Enter. Bow01 fills the viewports. In the Modifier panel, Stack view, highlight XForm to exit sub-object Gizmo mode.

Figure 4.32. Apply the XForm modifier and scale it 500 percent uniformly in all three axes.


caution

The XForm modifier is the only modifier that automatically switches to sub-object mode. You must remember to exit sub-object mode before proceeding after you make adjustments.

3.
In the Perspective viewport, select Stern01 and repeat Step 2 to resize it by 500 percent. Click Zoom Extents All to fill the viewports with the objects, and you see they are out of alignment because they have different scaling centers.

4.
Use the Align tool to realign them. In the Perspective viewport, make sure that Stern01 is selected. On the main toolbar, click the Align button and, in the Perspective viewport, click Bow01. Align is using the World coordinate system to determine the axes. In the Align Selection dialog, check the X Position check box. In the Current Object column, check Maximum, and check Minimum in the Target Object column. This aligns the butt ends. Click the Apply button to set the alignment and reset the check boxes, but remain in Align. Check Y Position and Z Position and check Minimum in both Current and Target Object columns (see Figure 4.33). Click OK.

Figure 4.33. Use the Align command to align Stern01 to Bow01.


5.
Select both objects in the Perspective viewport, right-click, and choose Convert To and Convert to Editable Poly in the Quad menu. This collapses the modifier stack to “bake in” the scaling of the XForm modifier.

6.
Select only Bow01 and, in the Modify panel, Edit Geometry rollout, click the Attach button and pick Stern01 in the Perspective viewport. This attaches the two objects into a single editable poly. Click the Attach button to deactivate it and rename the object Hull01.

7.
Save the file; it is already named Ch04_Boat02.max.

Setting Up the Boat Length

You have attached the two Editable Poly objects into a single editable poly object, but you realize that the boat is not the right length. In Exercise 4.7, you learn about sub-object Element editing and you clean up Hull01 to prepare to make it a continuous object.

Exercise 4.7 Element Sub-Object Editing

1.
Open the file called Ch04_Boat02.max on the CD-ROM or from the preceding exercise. From the File pull-down menu, choose Save As, point to an appropriate subdirectory on your hard drive, and use the plus sign button to save a new file with the name incremented to Ch04_Boat03.max.

2.
You have one object in the scene. If you select Hull01 in the Top viewport, go to the Utilities panel, and click Measure; you see that the bounding box dimensions—that is, the outside dimensions—are reported at the bottom and that the length is 131 feet (rounding up to the nearest foot; see Figure 4.34).

Figure 4.34. Use the Utilities panel, Measure tool to find information about the selected object.


3.
If you click the File pull-down menu and choose Summary Info from the menu, you see notes have been added in the Description area about the boat sizes (see Figure 4.35). The current length is 131' and the commissioned length from the notes is 258'6". Close the Summary Info dialog. This means the bow section must be moved 125'6" to in the positive X-axis of the Top viewport to be the correct overall length.

Figure 4.35. From the File pull-down menu, choose Summary Info to see notes that have been entered to describe the size of the original boat.


4.
In the Modify panel, Stack view, highlight Element sub-object level. In the Top viewport, pick the bow end (right), and the entire element that was defined by attaching two objects together turns red. Click the Select and Move button to activate it, make sure Offset Mode Transform Type-in is toggled on, and enter 125.5 in the X-axis numeric field in the status bar. Press Enter and the bow moves to the right. Click Zoom Extents All. Exit sub-object mode and open the Utilities panel. The overall length of Hull01 in the Measure panel is now 256'6" when rounded up.

5.
Now, remove faces from the flat areas to open the hull for connecting and welding in the next exercise to close the gap between bow and stern. In the Modify panel, Stack view, highlight Polygon sub-object mode. On the main toolbar, click the Select Object button, click in a blank area in the Top viewport to deselect everything, and toggle from crossing selection mode to window selection mode. Drag a selection window that includes only the flat inside ends of each element (see Figure 4.36). Press the Delete key to delete the end caps of the sections. Exit sub-object mode.

Figure 4.36. In sub-object Polygon, using window selection mode, drag a window to include only the end caps of each hull section.


6.
Save the file. It is already called Ch04_Boat03.max.

note

Looking at the stern section to the right in the Perspective viewport, notice that the backside of the boat seems to have disappeared. It has not. You are seeing the effect of face normals. Face normals that point toward the viewer are visible; face normals that point away are invisible.


Adding Segments to the Hull and Closing the Gap

In Exercise 4.8, you learn to add segments to the hull by cloning edges. You then weld the vertices from stern to bow to close the gap and make the hull one closed 3D object. You've already learned about welding selection sets of vertices into a common vertex that is at the geometric center of the selected shape vertices in Chapter 3, Exercise 3.7. In this exercise, you weld individual mesh vertices to target vertices. This ensures that one of the vertices, the target vertex, remains in place, which offers another level of control.

Exercise 4.8 Edge Cloning and Target Welding of Vertices

1.
Open the file called Ch04_Boat03.max on the CD-ROM or from the preceding exercise. From the File pull-down menu, choose Save As, point to an appropriate subdirectory on your hard drive, and use the plus sign button to save a new file with the name incremented to Ch04_Boat04.max.

2.
Select Hull01 and in the Modify panel, Stack view, highlight Edge sub-object level. In the Top viewport, drag a selection window around the right end edges of the stern section (see Figure 4.37).

Figure 4.37. In Edge sub-object level, drag a selection window around the right edges of the stern section as seen from the Top viewport.


3.
On the main toolbar, click the Select and Move button. Hold the Shift key and move the selected edges in the positive X-axis about ? of the way across the gap. This clones the edges and creates new faces. Repeat this three more times, each about the same distance until the gap is almost closed (see Figure 4.38).

Figure 4.38. Clone the edges four times to make four new segments that almost close the gap.


4.
Activate the Perspective viewport and zoom in on the gap between the bow and stern section. Highlight Vertex sub-object mode in the Stack view. In the Edit Vertices rollout, click the Target Weld button. In the Perspective viewport, click and drag from the back top vertex on the stern to the corresponding vertex on the bow. You see a dotted line when you are dragging (see Figure 4.39). Release the mouse button and the vertices are welded.

Figure 4.39. In Edit Vertices rollout, click Target Weld button. Drag from the stern vertex to the corresponding bow vertex.


5.
Repeat step 4 to weld all the vertices around the hull gap. You have to Arc Rotate to view them, and it is easier if you maximize the Perspective viewport. Click the Target Weld button when you finish to disable it. Go to Select and Move and carefully move the vertices in the Y-axis of the Perspective viewport to “fair” or smooth out the curvature of the new hull sections to the stern and bow (see Figure 4.40).

Figure 4.40. Target Weld the vertices of the stern to corresponding vertices of the bow all around the gap. Then, move the new vertices in the Y-axis of the Perspective viewport to “fair” the lines and smooth the transition.


tip

Don't worry. There is a finished half hull waiting if you hopelessly mess this one up. You sometimes need to practice a bit working in the Perspective viewport before it feels natural.

6.
Exit sub-object mode and save the file. It is already called Ch04_Boat04.max.

Smoothing Groups

In Exercise 4.9, you learn about an important concept called smoothing. The viewport display and the renderers have the capability of making the edge between two adjacent faces a hard edge or a smooth, blended edge.

This is all controlled by smoothing groups. It is simple: If two adjacent faces share a common smoothing group number, the edge is smoothed. Otherwise, the edge is seen as a sharp, faceted line.

Smoothing group numbers can be assigned to selected faces at sub-object level or by applying a Smooth modifier. Smoothing group numbers can also be automatically applied based on the angle at the shared edge.

Objects are also automatically assigned smoothing group numbers at creation time based on various rules.

In Exercise 4.9, you select sets of polygons and assign smoothing group numbers at sub-object level to form hard edges in the hull where you want them.

Exercise 4.9 Applying Smoothing Group Numbers at Polygon Level

1.
Open the file called Ch04_Boat04.max on the CD-ROM or from the preceding exercise. From the File pull-down menu, choose Save As, point to an appropriate subdirectory on your hard drive, and use the plus sign button to save a new file with the name incremented to Ch04_Boat05.max.

2.
Right-click the viewport labels for Top, Front, and Left, and set the viewport to wireframe mode. Activate the Perspective viewport and make sure nothing is selected in the scene. Notice that the bow and stern appear smooth, whereas the midsection looks faceted (see Figure 4.41). Select Hull01.

Figure 4.41. The bow and stern appear smooth, but the midsection of the hull is faceted. This is caused by the smoothing group assignments of the polygons.


3.
Right-click in the Left viewport to activate it. In the Modify panel, Stack view, highlight Polygon. Make sure Ignore Backfacing is clear in the Selection rollout. On the main toolbar, click the Select Object button and make sure you are in window selection mode. In the Left viewport, drag a selection window to include all top-deck polygons (see Figure 4.42). The top deck turns red and you should see 19 polygons selected in the Selection rollout.

Figure 4.42. In window selection mode, drag a window to select all the top-deck polygons in the Left viewport.


4.
In the Modify panel, Polygon Properties rollout, click the Clear All button, and then pick the 1 button in the Smoothing Groups matrix (see Figure 4.43). The 1 button becomes highlighted in yellow. All the selected polygons are assigned smoothing group 1, and their edges smooth to each other.

Figure 4.43. In the Polygon Properties rollout, click the Clear All button, and then highlight 1 in the Smoothing Groups matrix to assign Smoothing Group 1 to each selected polygon.


5.
On the main toolbar, toggle the selection mode to crossing. In the Left viewport, drag a crossing window through the gunwale polygons (see Figure 4.44). Remember that crossing selects all entities within or touching the window. Window mode selects all entities completely within the windows. In the Polygon Properties rollout, click Clear All, and then highlight the 2 button in the matrix.

Figure 4.44. On the main toolbar, toggle to crossing selection mode and drag a window through the gunwale polygons.


note

The numbers themselves have no meaning. You could have just as well assigned 21 or 4 to these polygons.

6.
To make the next selection easier, select faces by the previously assigned smoothing group numbers and then add to the selection set. In the Polygon Properties rollout, click the Select by SG button. In the Select by Smooth Groups dialog, highlight 4, 5, 6, 7 (see Figure 4.45). Click OK. This selects all other polygons that have had these groups assigned automatically at creation. In the Front viewport, hold the Ctrl key and drag a crossing window through the bottom polygons of new the midsection (see Figure 4.46).

Figure 4.45. In the Select by Smooth Groups dialog, highlight 4, 5, 6, 7.


Figure 4.46. Hold the Ctrl key and drag a crossing window through the bottom polygons of the new midsection.


note

You will probably find it easier to use all viewports and zoom in and out as necessary to select all the faces. Take your time; if you make mistakes, click in a clear area and start again. Creating selection sets is something you will do all the time in 3ds max 6, and after a little practice, it becomes a natural process.

7.
In the Polygon Properties rollout, click the Clear All button, and highlight 3 in the Smoothing Groups matrix.

8.
In the Left viewport, click in empty space to deselect all, and use crossing window with the Ctrl key to select all the polygons of the keel, including the vertical polygons at the bow (see Figure 4.47). This also selects most of the flat faces that cap the center of Hull01. That is okay. In Polygon Parameters, click Clear All, and assign 4 to the selection. Click Editable Poly in Stack view to exit sub-object mode and click in empty space in the Perspective viewport. You see clear edges in the shaded view at the transition point of smoothing groups (see Figure 4.48).

Figure 4.47. Using a crossing window selection and the Ctrl key, create a selection set for the keel and bow stem.


Figure 4.48. Exit sub-object mode and clear the selections to see clearly defined edges at the transition of smoothing groups.


9.
Save the file. It is already named Ch04_Boat05.max.

Making the Hull Whole

So far, you succeeded in creating a beautiful half hull of your boat quite easily. So now it's time to create the other half, right? No…no need to do that. You could copy this half with the Mirror command, and then go through the process of trimming and welding, but there is a better way: the Symmetry modifier.

In Exercise 4.10, you apply the Symmetry modifier to mirror, trim, and weld in one operation. It also enables you to adjust the trim point just where you want it at any time.

Exercise 4.10 Applying a Symmetry Modifier to Create a Whole Hull

1.
Open the file called Ch04_Boat05.max on the CD-ROM or from the preceding exercise. From the File pull-down menu, choose Save As, point to an appropriate subdirectory on your hard drive, and use the plus sign button to save a new file with the name incremented to Ch04_Boat06.max.

2.
In the Top viewport, select Hull01. In the Modify panel, Modifier List, choose Symmetry. You see that the hull mirrors itself along the X-axis, but the new object has two bows and the stern is completely gone. This is the trimming and welding action (see Figure 4.49).

Figure 4.49. Applying the Symmetry modifier to the hull mirrors it in the X-axis and trims the stern.


3.
In the Modify panel, Parameters rollout, check the Mirror Axis Y radio button. The hull now mirrors down the center along the keel axis. In the Left viewport, you can see that the keel is missing, however (see Figure 4.50).

Figure 4.50. Mirroring in the Y-axis completes the hull correctly, but cuts off the keel.


4.
In the Modify panel, Stack view, expand the Symmetry modifier and highlight the Mirror sub-object level. This puts you into move mode and the mirror plane turns yellow in the viewport. In the Left viewport, click and drag the X-axis Transform gizmo arrow and move the half hull to the right until you separate the two halves (see Figure 4.51).

Figure 4.51. Moving the mirror plane in sub-object Mirror far enough in the positive X-axis of the viewport separates the two hull halves.


5.
Move the mirror plane back just far enough for the halves to slightly overlap and you will have a complete hull with trimming and welding handled by the modifier. In Stack view, exit sub-object Mirror mode by clicking Symmetry. The result is a well-defined boat hull, as shown in Figure 4.52.

Figure 4.52. Exit sub-object mode for the Symmetry modifier and you have a complete hull object.


6.
Save the file. It should already be called Ch04_Boat06.max.

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