Join Dave Schultze for an in-depth discussion in this video Lighting strategy: Setting up the material override, part of Rhino and V-Ray: Architectural Rendering.
- In this video I'll cover a very specific type of material called the override and you will love how this works. The coolest part is it works anytime whether or not your model has any materials already assigned. Besides being a fantastic shortcut to get nice renders fast, it's actually perfect for our lighting exposure analysis. We'll cover that towards the end of this video, so what is it? Well the override is a single color material, typically gray and with one simple setting is assigned to all geometry in your entire scene.
Next up is where do we find this? We're going to go to the V-Ray options and at the top panel, under global switches we have override materials currently off, I'm gonna turn this on. Then we do have to select a color. Right now it is a medium gray. The color you select should be representative of the average color of all your building materials. Now what are my walls and concrete, are kind of light gray. I'm going to move this up, a little bit lighter, maybe about 75 or 80%, that will be a much more realistic average.
This is important because we're going to look at the rendering results in the light areas and the shadow areas, so that will help us determine the proper camera settings for following renders and we'll get to an optimum solution quicker, hit okay. I close global switches. Couple of things you might want to check the beginning of a rendering session, is under the general preset here, this controls quality. I'm going to go ahead and say medium quality, click on the green check mark, it will populate all the areas relating to quality.
I'll double check my camera so that is physical camera on, F number eight, film speed 100, and since we're exterior, we're going to start with a one over 300 exposure or shutter speed. Let's close that. Typical the next thing I check is just the output size. I've got this aspect ratio roughly to the one in the perspective view port, so this will work just fine, we'll close that. Can move this out of the way. Just make sure this view port is selected and that means it's highlighted, then we start the rendering with the R button here for render, let's check it out.
Okay so the rendering is done and even though the same materials used everywhere this is still very informative. We're able to see the exposure from the camera. We're able to see sunlight and shadows and we can actually make a lot of decisions based on this. Now my camera shutter is probably set correctly but if it was off, a little bit too light or dark, I could make that adjustment quickly and easily. One thing I'm noticing though, this is more of a personal preference, is our glass curtain wall here. This the two-storey cylindrical drum, that is also reading as opaque.
I think this would be way for effective if we excluded that one material from all of the other overrides so that's very easy to do if we go to the material editor. Move this out of the way. Click on the M button here, under V-Ray toolbar and that material is called clear glass. We have a lot of settings here, I'm just going to focus on the most important ones. Under options, most materials by default can be overridden so we can turn that off, so it can't be overridden.
Which is another weird way of saying you're overriding the override. With that one little change, let's make sure our perspective is still selected and if that's the case, you can actually do a little shortcut here clicking on these little teapot, it will render the last view port. With all of its settings, let's go ahead and start that. Okay so that one little changed the glass, makes this look so much better. Go ahead and exclude any materials you feel are critical to reading the scene and for sure I always pick the glass that's my preference to keep things easy and quick.
There's another adjustment here and this is actually a very challenging render because we're looking at an exterior with interior portions revealed. This is really the most challenging scenario you can imagine. We're having dark areas and light areas all in once scene, so this exposure like I said looks pretty good, so what I'm going to recommend we use from time to time as needed is the levels and this can really pull together a lot of the problems you typically have and fix them all in one shot. There's two ways we got to get this going. On this corrections controls down here at the bottom, we click that, open up this panel.
This actually has multiple ways. We're gonna focus right here on this gradient or levels, but it's not going to be applied unless we click the second button here, that is use the levels. The basic premise is we make the brights a little bit brighter. This is actually getting fairly bright, I don't want to go to far but I think the darks can definitely be a darker so we're going to pull this area over in the black section and pull that down, so I don't wanna go too far, this is definitely move the scroll there.
Just kind of leave it there and we could tweak it for a lot longer. The basic premise is we've just increased the contrast so we can save ourselves typically a couple passes of rendering just by using the level of control. Let's do show the before and after, if I click over here so this is the before, it now looks in comparison a little bit flat and now we click use the levels, we're seeing that much more saturation in there. Let me close those guys. I'm going to show you another personal preference to get better feedback in the view ports here.
We're going to double click on this perspective view port and as we move around, I'm noticing shaded view is a really, a good way to view the scene. We don't want to have the rendered with all the texture maps just slowing down the video card but again, I would like to see the glass be transparent so there's actually a way we can do this in the view port as well. First, I'm going to select all the glass in the scene. We have this curtain wall, we have a couple doors, we have a skylight, let's go ahead and use the material editor to select all of the glass material so I'm going to right click and select all objects using this material.
Let me close this, this will now all be highlighted. You can see the skylight and the doors. Under Display we have this object shading attributes, it's basically a view port override, so I'm gonna click that. It normally by default uses whatever the view is telling it, currently that's shaded so we're going to select that and say from now on, you will be rendered. I right click to complete, we now have a mixture of shading modes in the view port. Everything is shaded and the glass is rendered.
Check it out, this is really handy and it actually helps me a lot, just kind of visualize things and maybe even saves a step or two of rendering. The advantages of using override material are very powerful, whether using it for quick render studies, lighting analysis or both. Once you try it, it predicts you'll wonder how you ever live without it, it's that good.
- Setting up your system
- Understanding the settings, software, and process
- Lighting the scene
- Tweaking exposure
- Rendering with architectural glass, masonry, and concrete
- Making realistic grass and trees
- Creating depth of field
- Compositing from 3D to 2D