Wire and Isoline Clay Render in 3DS

Picture 1. Three wire clay render methods in 3DS MAX.

27.08.2007 Category: 3D (Rendering)
In 3D graphics the structure of the model often matters a lot. Well built model renders and animates nicely. When a clay render is created out of a 3D model, one often wants to show also the structure of the model. In this tutorial I cover clay rendering where also the structure (wire / edges) of the model is shown as addition to the surface.

Wire Clay Render in 3D Studio MAX

In 3D Studio MAX it's simple to see edges of the model in real time hardware shading but it's not that simple to make them visible in rendering. However, there are several ways to make edges of the model appear in the final rendering.

Face Map (Scanline and Mental Ray Renderers)

Picture 2. Turn Face Map on and select Gradient Ramp as diffuse map.

Picture 3. Settings of Gradient Ramp.

Picture 4. Mental Ray rendering where Gradient Ramp works as Face map.

By using material's Face Map option texture can be mapped precisely inside of a polygon. The edges of the model can be made visible by using the following settings in the default material (pictures 2 and 3):

• Face Map: Enable
• Diffuse Map: Gradient Ramp
  • Blur: 0,01
  • Gradient Type: Box
  • Interpolation: Solid
  • By adjusting the place of the change in color you can control the thickness of the edges

If you are rendering with Scanline turn SuperSampling on and if you are rendering with Mental Ray increase sampling quality so that thin lines are rendered accurately enough. Picture 4 has been rendered by using the method described above. For some reason some of the edges seem to be thicker than others.

Composite Map (Mental Ray Only)

Picture 5. Select Standard material to Mat.1.

Picture 6. Settings of wire material.

Picture 7. Mental Ray rendering where wire material is in composite map.

Another method to make edges visible in rendered image is to use composite map:

• Select your clay material in material editor.
• Click on top of Standard and select Composite as material type according to picture 5. 3DS MAX asks whether you want to keep or discard the old material. Click OK so that your old material is saved as Base Material of the Composite material.
• Click on the first material (Mat. 1) of Composite material and select the type of the material to be Standard and give it a name Wire (picture 5).
• Enable Wire in the Wire material according to picture 6 and select suitable diffuse color for the material. When Wire is enabled the material is shown only in the edges of the model. If necessary you can change the thickness of the wire by adjusting the Size value in the material's Extended Parameters section (picture 6).

Picture 7 has been rendered by using the method described above. Wire-option makes all the lines to be equally thick. In other ways the result is very similar to the method with Gradient Ramp map.

The Problem with Face Map and Composite Map

The problem with the both methods may be that they make all the visible edges to appear in the rendering. Often the geometry of the model is very dense and edges are very close to each other. The net of edges might be too dense. You might be able to affect that. For example if you are using Meshsmooth modifier you can turn that off while rendering. Of course this makes the model rough and angular like the leg of the turtle in pictures 4 and 7.

Isoline Clay Render in 3DS MAX

Picture 8. Extract Isolines to separate object.

Picture 9. Enable in renderer makes the lines to show up in rendering.

Picture 10. Model and edges have been rendered with Mental Ray as separate objects.

If your model is so called Subdivision surface which is created by subdividing the surface to smaller polygons using Meshsmooth or Turbosmooth modifier you can use the following technique. When Meshsmooth modifier is added to your model the surface smoothens and is divided into smaller parts according to Iterations value. By default Isoline Display is turned on in Meshsmooth modifier which means that even if there are many new edges because of the modifier only the original edges are shown. That is how you see the model when you turn on Smooth + Highlights and Edged Faces in a view. In the following I cover the rendering of this kind of view. So we are going render a surface where only the edges according to Isoline Display setting are shown.

Extract Isolines as Edges

• Add Edit Poly modifier into the modifier stack just below Meshsmooth modifier. (You don't have to do this if Meshsmooth modifier is already on top of Editable Poly or Edit Poly)
• Select all edges in Edit Poly modifier.
• Click on Meshsmooth modifier. Now Meshsmooth modifier is applied to all edges.
• Add Edit Poly modifier on top of Meshsmooth modifier.
• Activate edge sub-object mode and click settings button next to Create Shape button.
• Select Linear as Shape Type and click OK (picture 8).

Now isolines are a separate shape object which can be rendered. Turn on Enable in renderer in the new shape object according to the picture 9. Thickness value can be used to control the thickness of the lines. Picture 10 has been rendered by using the method described above.