THE COPPER TOAD TUTORIAL

This tutorial shows how to combine three tools to obtain the effect of weathering on the copper toad head contained in the PT_MultiPatinae demo scene.




This will be achieved with the following steps:

  • 1.Apply the PT_Multipatinae shader to cover the Softimage default material with two different layers evenly distributed on the object surface.
  • 2.Use the PT_TurboTxt shader to generate a turbulence texture that we'll use to modify the distribution of the upper layer.
  • 3.Use PT_MapGen to generate a picture representing the information of concavity of the object's surface that we'll use to drive the polishing operator of PT_Multipatinae.

Once the scene has been loaded, Softimage looks like this:

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Open the material editor:

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The toad has a shiny copper material applyed.
The rough render at this points looks like this:

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Let's now load PT_Multipatinae from the MATERIAL_SHADERS chapter of the Shader_Lib database:

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The dialogue is divided in four different areas:

  • A.Lower Layer: allows you to define the properties of the first material that will be applied on top of the default Softimage one.
  • B.Upper Layer: describes the second and top layer which will be applied (and blended) on top of the Lower one.
  • C.Polishing: defines how much the layers are corroded starting from the top down, until the Softimage material appears.
  • D.Area to key frame the parameters and preview the effect.

Define the two layers as follows:

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Being the Polishing to 0, the preview only displayes the upper layer as defined in the shader:

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Making the Polishing Thickness range between 0 and the sum of the Lower Thickness and the Upper Thickness, you can make the material shift from the Upper layer down to the original Softimage material.

Let's now define two textures, to be used as arguments for PT_MultiPatinae.

Choose Texture->2D_Global and load PT_TurboTxt from the TEXTURE2D_SHADERS chapter of the Shader_Lib database.
Set the parameters as follows:

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This shader generates a turbulence pattern looking like this:

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Now, go back to PT_Multipatinae and edit its parameters in order to use the turbulence pattern to modify the distribution of the upper layer.

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At this point, the render would look like this:

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Let's now generate the polishing map.

In the schematic view, select the second dummy texture and choose Texture->PT_MapGen.
Set the parameters:

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Clicking Ok, PT_MapGen will render the concavity picture.
After it's done, it is automatically put in place of the texture you had selected before choosing PT_MapGen, and looks like this:

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The picture is made so that once mapped on the model, the black zones correspond to high curvature points, while white zones cover flat sections of the model.

Let's now use the map.

Open again the material editor and edit the PT_Multipatinae shader.
In the Polishing section:

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Accept the values. We're now ready for the final render:

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Phoenix Tools srl (c) 1998 all right reserved. - Tutorial by Cefalo Peruzzo - The TOAD appears courtesy of Riccardo Russi.

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