Join Brian Bradley for an in-depth discussion in this video V-Ray map types: MultiSub Tex, part of SketchUp: Rendering with V-Ray 3.
- [Instructor] One very handy utility map that we now have available in V-Ray for SketchUp is the Multi Sub Tex offering that can help us add all sorts of variety and detail to a scene in a very short space of time and whilst we will only look at two very quick uses for the map in this particular exercise, the creative ways in which it could be utilized are really endless. To see how this map type works, let's open up the Asset Editor and take a look at what we have in the scene and in the materials list.
Well, in the scene we have as you will already have noted a number of objects that have had this multicolored material applied to them. Now, despite its name, the material is using just a single blue color in the diffuse channel, hence what we see in the SketchUp view port. All of that is about to change though as we make use of the Multi Sub Tex map. Now, of course, the example that we are using here is a little bit contrived in that we have just added this single material to all of the objects on these shelves that are sitting inside the rendering camera's field of view.
Imagine though that this was a shelf full of more uniform looking objects such as say books or maybe fruit drink cartons and we just needed a way to quickly add some randomization to the way that they look only without having to go through and create four or five different materials. Well, this is where the Multi Sub Tex map can come into its own. After clicking on the map button in the diffuse slot then, let's add a Multi Sub Tex map and take a look at the options that we have with the two big ones here being the get ID from dropdown that houses a number of ways in which we can apply the randomization that we want and the add texture button which we can go ahead and click five times in order to add five entries to the texture list.
This essentially is the part into which V-Ray will dip in order to pull either colors or textures that it can use in the randomization process. As seeing this in action will probably make it much clearer to us than my trying to explain it, let's go ahead and add different colors to the entries that we have made here, although again, we could just as easily be using map types in these slots if we wanted. Once we have those added, let's also make a change to the ID numbers so that instead of starting at zero, they start at one simply because V-Ray seems to find this easier to work with in my experience.
Once all of that is set up, all we need do is choose an option from the get ID dropdown. Now, obviously, how you have created and set up the geometric objects that you are working with will go a long way towards influencing the option that you choose here. In this particular scene random by render ID seems to work best. With that chosen, let's go back up to the material level and take a render. Sure enough what we get back from that is our five colors distributed across the various objects in the scene in a semi-automated way.
Of course, as we have already noted, this was just a very obvious way in which we could look at the basics of how the Multi Sub Tex map works. With a bit of imagination and experimentation there are lots and lots of ways in which this map can be used to help add variation and even apparent randomness to materials that we are creating. For instance, let's go ahead and cut this map from the diffuse channel and set up a basic glass material here, so diffuse to black, reflect to white, refract to white, after which we can take a render.
What we see now is that we have shelves full of slightly smoky looking glass objects. To add variation in this case all we need do is paste our Multi Sub Tex map into the fog color channel. We can brighten each of the colors quite a bit so that the fog effect isn't too strong and when we take a render now, we get to see just how easy it is to add variety to a whole bunch of objects that remember, still have just a single material applied to them.
That is the power of the Multi Sub Tex map.
- 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