Join Brian Bradley for an in-depth discussion in this video V-Ray map types: Dirt, part of SketchUp: Rendering with V-Ray 3.
- [Instructor] Although the texture map that we will look at in this video is in no way new to V-Ray for SketchUp, the fact that in certain situations it can rank as one of the more important texturing tools available makes it a no-brainer for inclusion here. We are in this instance talking about the dirt map which can be used to create effects such as dirt that has been collected in the crevices of an object or even to create a separate ambient occlusion pass using render elements. To take a look at how the dirt map works, let's open up the Asset Editor and access the parameters for our base gray material.
Now, we have already noted that this particular map type can be used to create a variety of effects but again, perhaps the easiest way for us to visualize how it works is to apply it to the diffuse channel of our material. Before we do that though, let's right click on the color swatch here and copy the color value that we have after which we can click on the map button and assign a dirt map to the diffuse color swatch. Now, because the default unoccluded color on the map here is white, taking a render at this moment in time would give us a very blown out looking object indeed given the exposure settings that we have in the scene.
Of course, sometimes white is exactly the color that we will want to use in this slot such as when creating an ambient occlusion pass but of course, white isn't the only color that we can use, so for instance, let's go ahead here and right click on the unoccluded swatch and paste the gray value that we copied earlier. If we take a render now, we should see a very obvious occlusion effect taking place although sometimes it can be hard to figure out just which shadow details are coming from the lights and GI systems in the scene and which are coming from the dirt or ambient occlusion shader that we just added.
A quick debug trick then is to set the occluded color to something that will be obvious in the scene, let's say red in this instance and then render again. Now as we look, we're in no doubt as to what is being affected by our dirt map which puts us in the perfect position to check how the map controls work. The radius control, for instance, is used to determine how far the occlusion effect can travel on the geometry surface. In fact, before we go ahead and change that, let's initialize an interactive render here so that we can see things update on the fly as it were.
Setting the radius value to five then gives us a much boarder spread of the occlusion whereas dropping it down to 0.5 gives us a really tightened effect. Let's just reset that to one and take a look at the fall off control which numerically speaking actually works the opposite way around to what you might expect given that the value determines the speed at which the fall off occurs, not the distance and so, if I use a value of one here, we again get a tighter looking occlusion effect.
Again, let's reset that back to zero and this time enable the same objects only option. What we see now is that the shader ball head and base essentially ignore one another as far as the ambient occlusion effect is concerned and so, it will only add occlusion to the internals of each distinct piece of geometry. If we then tell the dirt map to also ignore self-occlusion, well, we get no occlusion effect at all but we could at this point also uncheck the same objects only option and so create occlusion only where the objects meet.
Finally, if we uncheck everything here and enable the environment occlusion option, we are now using the environment color in unoccluded areas rather than the one set up on the dirt map itself and so, if I come to the environment rollout in the settings tab, I change the environment color to say green, then that is exactly what we see show up in our render.
- Gamma handling in V-Ray 3 for SketchUp
- Working with interactive rendering
- V-Ray light types
- Working with irradiance mapping
- Rendering animations
- Working with the V-Ray camera
- Using the Materials UI
- V-Ray FX tools
- Stereoscopic 3D rendering
- Using V-Ray objects