LightWave surfaces with the node editor
The nodal surfaces in LightWave are pretty neat and allow for some complex surfaces to be made. Surfacing like this is still quite new to me so I am going to start documenting the node set up for some surfaces here on this page. There probably will not be too many surfaces here (not enough time for 3D!) but I will add to it from time to time.
Ambient Occlusion with Diffuse Texture
Here is a set up for Ambient Occlusion that can be mixed with a user specified diffuse texture:
| Node | Purpose |
|---|---|
| Scalar - Base Diffuse | Base diffuse value for the surface |
| Scalar Layer - Diffuse Texture | Texture layer to control the diffuse value for the surface; layer opacity blends with the base diffuse value exactly like the old Layers based surfacing. |
| Occlusion | Ambient occlusion node that calculates the occlusion for the surface geometry. |
| Scalar - W | Weight of the ambient occlusion effect. This has range [0,1]. When W = 1, then the ambient occlusion effect is strongest. |
| Subtract(1) | Performs (1 - W) |
| Multiply(2) | W * Occlusion |
| Add(2) | W * Occlusion + (1 - W) |
| Multiply(1) | Produces final diffuse value: [W * Occlusion + (1 - W)] * (Diffuse Texture Layer) |
The effect of W is to set a minimum value (1 - W) that the ambient occlusion produces. Thus, the larger the weight W, the larger the effect of the ambient occlusion. Changing the weight W allows control of the ambient occlusion amount. Note that it seems that all the scalars output values between [0,1].
Subsurface scattering
For the compact fluorescent elight bulb modeling tutorial, I investigated using the subsurface scattering (SSS) node for making the light bulb tube translucent:
I found out that the SSS node does not work very well with point or distant lights. I set up the scene with a few area lights, at least one of which is behind the object for a subtle translucency effect:
Here is the nodes setup:
Settings for each node:
I mixed both Lambertian and SSS nodes for the diffuse shading. Scale(1) is set to 50% and Scale(2) is set to 100%. This controls the relative mixing of the two surface types.
Discussion
I had been trying to learn how to combine SSS with other diffuse nodes. Your awesome tip about using a vector scalar really made things click.
Thanks again!
-Darrick