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Chapter 7. Non-Organic Modeling for Broa... > Building a Toy Fire Truck Using Poly...

Building a Toy Fire Truck Using Polygonal Modeling Techniques

You will use polygonal techniques in this chapter to create a model of a toy fire truck. To make this a bit more interesting, there is only one Perspective view for the reference photo of the model toy. Perspective warps the appearance of the proportions and makes it harder to determine the dimensions of the truck. You will have to get the proportions for relative measurements off the Perspective view.

Exercise 7.1 Creating the Truck Body

Start by creating a box with 3 length, 3 width, and 3 height segments.

Go to Edit/Clone and make a copy of the box to use as reference.

You will modify the original, which will update the reference with the Meshsmooth modifier.

Apply a wireframe texture to it (F3) and a Meshsmooth modifier. You can access this tool by going to the Modifier panel, selecting the More button and then selecting Meshsmooth from the list of available modifiers. By default, the iteration level is set to 0, so go to a value of 2, as seen in Figure 7.1.

Figure 7.1. Start by using a box with segment 3×3×3.

One of the best places to start the modeling process for box modeling is from the Profile view (see Figure 7.2), which is where you will start for this exercise. You can also work in another orthogonal view, such as the Top or Front views.

Figure 7.2. Here modeling has been done in the Profile view and then a bit more in the Top view, using the Perspective window to check the work.

You will build the truck’s parts to a rough point and then build the other parts of the truck. Then you’ll go back to modeling the specific details of the truck. This is useful so that you don’t overwork an area and then have to change it when you have moved to another object. So, for this exercise, you will begin by sculpting out the front cab’s curve for the negative space for the wheels. You will do this using by modifying the area with Edit Mesh modifiers and with a Free Form Deformer (FFD) modifier. You will then pull up the vertices and modify them to make a curve for the wheels.

Start to work on the top part of the cab: Select all the top faces and extrude them. The extrusion is found in the Face level of an edit mesh. The number of extrusions is determined by the corresponding number of control edges.

As you extrude them, in the Top view apply scaling operations to create the ridge in the front of the cab, as seen in Figure 7.3. These scaling operations to taper the top portion of the cab will be best seen in the Perspective window, where you can see the changes in real time.

Figure 7.3. Here you have extruded the faces several times. Notice that there is enough detail for the window and the details in the top of the cab.


If you have moved the vertices on the face that needs to be extruded, this will cause errors with the extrusion. These errors will happen even if you move the vertices in a direction co-planar to the face. To avoid this, be careful about which vertices you are moving, and place a Slice modifier behind the faces to be extruded. Then select the faces to be extruded and select the Make Planar option.

The top of the cab needs to be rounded. This can be done with several modifiers, including edit mesh and FFD.

Using multiple modifiers and Sub-Object Level modifiers will help you get the results you want. However, be sure to constantly check all the views while you are modeling so that you are modeling in three dimensions (see Figure 7.4).

Figure 7.4. It is very easy to overwork an area in one orthographic perspective and then have to make more changes in all other views.

Using Figure 7.5 as reference, make visible the edges that will make up the window of the front cab. Do this on both sides of the truck.

Figure 7.5. Making edges visible or invisible affects how the model is shaded. It is very important during model construction that you are aware of which edges are visible and which are hidden because this can drastically affect the rendering.

The next step is to create the wheels.

Start creating one wheel by using a chamfered cylinder.

Chamfered cylinders are additional parametric polygons that max has under the Create tab, under Extended Primitives. Chamfer creates a rounded edge so that the lighting is not so harsh where the edges meet. Because they are parametric, they can later be modified interactively to get the desired smooth value on the edge of the cylinder.

Create the chamfered cylinder with 1 height segment, 4 filet segments, and 33 sides. (See Figure 7.6.)

Figure 7.6. Here you create the wheel.

Select the faces on the outer side of the wheel. Using the Spinner setting of the extrusion in the Face sub-object, spin any amount and then spin down to 0 and release the spinner.

The extrude of 0 creates a duplicate face that can’t really be seen until the selected faces are scaled back.


The zero extrusion techniques must be used with caution. You want to remember that you have done this operation, so perform a scalar operation that reveals that you have a zero extrusion. Even though it’s not visible, the doubling of faces can cause confusion with rendering problems and seams.

Without deselecting these faces, scale them in Profile view and repeat Steps 9 and 10 once more. Use Figure 7.7 as a reference.

Figure 7.7. Here is the result of the initial zero extrusion, which adds detail to the side of the wheel.

This will give you enough detail to add depth to the wheel instead of having a simple cylinder.

Now copy the wheel object as an instance and place the wheels where they belong on one side of the vehicle only.


An instance is a duplicate of the original geometry that maintains a direct connection to the original. Thus, if the original is modified, the instance updates to reflect this. If you modify the instance, the original matches any modifications done to the instance. Reference modeling works on the basis that the reference gets any modifications from the original, but the original model gets no modification information from the reference. Referencing and instancing also free up the machine from heavy computation.

Create the circular details on the side of the cab with chamfered cylinders. Create one chamfered cylinder, and place it in Profile view near the rear of the cab.

Mirror all the newly created objects, as seen in Figure 7.8.

Figure 7.8. Mirror the geometry. Make sure that you are working in the correct coordinate space if you have not created all the initial geometry in the middle of the origin.

Create a box that will be the rear of the fire truck, as seen in Figure 7.9.

Figure 7.9. Here you can see the beginnings of the volume of the truck being flushed out. You have not yet worked on the details because you want to get the truck’s proportions right before adding the details. This saves you from having to tweak the details because your volumes are wrong.

Select the top two rows of faces on both sides of the rear part of the truck, and extrude the shapes. Shape the top of the extrusions as you extrude them so that they resemble the rear portion of the truck’s windows, which come out from the base of the side of the truck.

Select the front faces of the truck. Extrude these faces to add the canopy area in the front of the truck. Use a Slice modifier (under the Modifier tab under More/Slice) to create a row of edges that will create a rigid edge to the corner when the Meshsmooth is applied. Use Figure 7.10 as a reference.

Figure 7.10. Here you see the relative placement of the slice. Careful placement of Slice modifiers during reference modeling can create sharp corners with the normally round Meshsmooth technique.

Add an Edit Mesh modifier and select the faces that will correspond to the windows of the rear of the fire truck. Extrude the faces and shape the top of the extrusions, as you did in Step 15. Figure 7.11

Figure 7.11. The resulting negative extrusions have created detail that will be used to create negative cavities for windows. shows the result.

Next you will do a negative extrusion on this face selection. You will see that when the Meshsmooth is applied at the end of the stack, the windows’ extrusion will have no definition and will be too undefined. You can see the difference when you add a Slice modifier to create some more definition in the corners of the window. Figure 7.12 shows only one Slice modifier. To get the other corners to look more defined, you will need to add three more Slice modifiers.

Figure 7.12. Here the slice has hardened the edge around the corners of the window.

Add three more Slice modifiers by right-clicking the Slice modifier and selecting Copy. This option copies the modifier. Then right-click the top modifier in the Modifier Stack and select Paste. This places the copy of the modifier after the last modifier in the modifier history. Repeat this step three times.

The copy of the modifier is created exactly over the original, so you will have to move the Slice modifier’s Sub-Object Slice plane to see different results. When you finish, your model should look like Figure 7.13.

Figure 7.13. Here all the corners have been sharpened—they’re much different than the rounded holes they were.

Next you will create the details on the top rear of the fire truck. The base object will be a chamfered cylinder. Some of the objects will need to be edited with face extrusions to get the shape needed.

First create a chamfered cylinder that will be the metal rod that is the hinge portion of the joint. Make the length a bit shorter than the length of the rear of the truck.

Make a copy and scale the radius to 30% and the length to about one-tenth of the original’s size. Duplicate it and slide it down the length of the truck. Place these in the middle of the rod, with an even spacing, and leave room on the ends for duplicates of them to be placed on the outer side. Duplicate them and place them on the outer side of the two cylinders.

The outer cylinder should be modified with an edit mesh. Select the bottom vertices and pull them down so that the object is not merely a cylinder, but more like a box with a rounded top. For the middle section, duplicate the rod cylinder and, using an Xform modifier, scale the radius and the cylinder up; scale the length to fit between the four larger cylinders.

This resulting cylinder should be smaller in radius than the four pieces on its ends.

Use an edit mesh and create irregularities in the surface that match Figure 7.14. Much of this modeling is free-form and small enough for the user to create a loose model that resembles the reference image.

Figure 7.14. Here you can see the details on the top of the truck. Although the details are seemingly subtle, they add extra crevices for the lights and shadows to play with and increase the reality of the model.

When this is done, mirror the objects.

Now you’ll create the ladder pieces. Start with a simple box.

To get the ladders’ split-tuning fork-like object, select the outside faces and extrude them. Figure 7.15 shows the result.

Figure 7.15. Here you have modeled some of the ladder’s pieces. Again, you are just laying the groundwork and adding details later.

Select the pieces that will extend past the base object of the ladder. Extrude these faces and round out the shape.

Add two slices near the middle of the second piece of the ladder, and then use this detail to extrude the small, thin detail ridge. Your model should look like Figure 7.16.

Figure 7.16. Continue to add the ladder by placing an object that will be the ladder’s canopy.

Go on to create the hubcaps and the bottom fireman’s canopy. Create the hubcaps by using a cylinder and using the same extrusion techniques used in creating the detail for the wheel. Create the fireman’s canopy by taking a box and using a negative extrude for the canopy; and then select the face and extrude it for the trim of the canopy. Figure 7.17 shows the result.

Figure 7.17. The finished detailing of the truck. All that was used were some simple extrusions.

Using some primitives, create the base of the bottom part of the fire truck. These are simple box primitives that have been shaped and rounded at some places. Other objects were duplicated. The result is mechanical detail, which adds to the intricacies of the model. Use Figure 7.18 as a reference.

Figure 7.18. The simple shapes are clustered together. Using repeating shapes, you can create mechanical complexity out of simple geometric objects.

Next, select the faces on the top of the cab and do a negative extrusion to get the fire truck’s cavity for the fire truck’s siren. To extrude in the negative value, make sure that you are in the Face Sub-Object mode under an edit mesh. Then drag the down spinner for the Extrusion setting.

Although this detail is not overly visible, it gives some interesting space for the light to play with, to affect the shading and rendering of the final image.

Model the siren from a simple box and place it into the cavity, as seen in Figure 7.19.

Figure 7.19. The siren is placed here.

You will use more simple box-modeling techniques to create the object on the top of the siren.

Create a box, and make sure that the segment settings for the box from the Top view are odd.

This generates the fin, which comes out from the top of the shape.

Taper the end coming toward the front end of the truck. Bend the shape of the box in the profile so that it follows the curve of the front cab. Select a few faces at the top the object, and extrude out the detail of the knob of the object.

Now that you have created most of the fire truck’s volume, you will to return to modeling the front cab of the fire truck.

The first thing you want to do is convert the object to an editable poly, as seen in Figure 7.20.

Figure 7.20. Select the object that you want to convert to an editable poly, and then right-click and select Convert to Editable Poly.


Editable poly is a new object type within 3ds max 4 that allows faces that are more than four-sided. You might prefer to use older polygon-modeling techniques, such as editable mesh, for more complex organic-modeling techniques, but editable poly is extremely useful in non-organic model creation.

One of the new settings in editable poly is the new sub-object Border, which editable mesh does not have. It selects all the edges in an open-faced area of an editable poly. This is useful for “capping” a surface. You should cap only flat surfaces because the results give you unpredictable shading in a curved surface. If you do cap a surface that is not flat, use this only as a starting point to develop the manner in which the edges are turned and what shape the faces will have. These all determine the shading of the model. See Chapter 9, “Organic/Character Modeling Using the Patch Method for Broadcast/Film,” for more details.

The bottom part of the front of the cab has been messed up during the editing of the vertices. You will use the Border feature in editable poly to fix this.

Select the vertices that are to be deleted (from the Profile view), and cap this open-faced surface with the Cap option, found in the Border sub-object of the editable poly.


The Border feature in editable poly calculates all the edges in an area of open faces within an editable poly. This can be capped, and the modifier does the best job to create a surface to close the hole. (See Figures 7.21, 7.22, and 7.23.)

Figure 7.21. At this point, you have deleted the bottom faces and are about to perform the editable poly Border option.

Figure 7.22. When using the Border sub-object in editable poly, select the open edge.

Figure 7.23. This is the end result of a border that has been capped with an editable poly.

Now you have a flat-faced object that you will detach as an object. Add an edit mesh, select Face Sub-Object mode, and click Detach. An option box pops up; select to detach as an object.

With the newly detached face, extrude down to create the fender of the front of the fire truck cab.

After you have extruded four segments, select the inside vertices of the wheel to curl to the wheel shape. Figure 7.24 shows the result.

Figure 7.24. After extruding four segments, select the inside vertices of the wheel to curl to the wheel shape.

In the front of the view of the fender, using the Edit Mesh modifier under the Modifiers tab, shape the vertices into the border of what will be the area of the negative cavity of the front of the cab.

Select these faces and then do a negative extrude. Do some tweaking with some carefully placed weighted vertices to get the result in Figure 7.25.

Figure 7.25. This shows the result of the negative extrude and the weighted vertices.

Use a chamfered box and some FFDs to create the piece that represents the license plate.


FFD stands for Free Form Deformation. This is a modifier that can be applied to any geometry type by going to the Modifier panel and selecting an FFD. The FFDs enable you to make global changes to an area via a lattice and control points. There are several types of FFDs, including 2×2×2, 3×3×3, 4×4×4, and an FFD box. In the FFD box, you can set the number of Free Form Deformer lattices.

Inspect the proportions of the model, and make any necessary adjustments.

In my initial modeling, the fender area was too small and the front cab of the fire truck was a bit too tall. Because I haven’t added too much detail, adjustment to proportion can be made with out too much pain. Figure 7.26 shows how your model should look at this point.

Figure 7.26. The resulting model should look like this.

Do a slight negative extrude on the face that represents the window of the front cab of the fire truck.

To add the front negative cavities in the fender of the truck for the lights, create two cylinders and Boolean them to cut the shapes into the fender. Figure 7.27 shows the result.

Figure 7.27. This shows the cylinders being placed before the Boolean operation.


Before any Boolean operation, save and increment save so that you always have the original shapes to go back to for changes and to safeguard your design in case the Boolean operation does not perform correctly.

Create a cylinder and make a copy. Attach the second cylinder to the first object so that you have only one object (one cylinder must be converted to an editable mesh or poly before you can attach the other cylinder to it). Select the fender. Then select Create Panel/Compound Objects and do a subtractive Boolean.

The Boolean might not give you the result you want. Convert the mesh to an editable poly and select the border of the rim of the light cavities. Cap the borders and then do a negative extrusion, as seen in Figure 7.28.

Figure 7.28. After the Boolean operation, your design should look like this.

Create the lights by creating a sphere and setting it to Hemisphere at.5. Then make a copy and place them accordingly. Figure 7.29 shows the result.

Figure 7.29. Place the lights in all views.

Draw a spline in Profile view to represent the connecting hose from the truck to the tip of the hose at the top of the ladder, as seen in Figure 7.30.

Figure 7.30. This is the spline representing the connecting hose.

Under the Modifier panel of the spline, check two settings, Renderable and Display Render Mesh (see Figure 7.31).

Figure 7.31. Set the spline renderable settings.

The Renderable setting enables the spline to be renderable; by default, it is unrenderable. The Display Render Mesh check box generates a mesh for any lofted geometry. These are new to 3ds max 4. Figure 7.32 shows the model at this point.

Figure 7.32. The model should look like this at this point.

Add a little detail to the base of the hose by adding a small chamfered cylinder. The final result is seen in Figure 7.33.

Figure 7.33. The final model should look like this.



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