From the course: SketchUp: Rendering with V-Ray Next

Working with irradiance mapping, part 1

From the course: SketchUp: Rendering with V-Ray Next

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Working with irradiance mapping, part 1

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- Because global illumination is such an important part of the rendering for visualization toolkit, even though things have become much simpler in this department in recent years, we're going to spend this chapter examining the GI engines available in V-Ray Next for Sketchup. In fact, for the 1st 2 videos, we're going to focus entirely on using V-Ray's irradiance mapping engine in order to test out how well it does at creating a basic global illumination solution for an interior shot. And, we have of course, purposefully chosen an interior setting because it represents, by far in a way, the the biggest challenge to lighting as regards getting a clean, believable GI-solution with which we can work. Indeed, the plain gray override material that we are also using on most of the geometria, will add to the difficulty given that it will easily show up any nice blotchiness being produced by the GI engines. With just the default V-Ray settings in place, of course, any new Sketchup scene that we create already provides a pretty decent GI setup that can, straight out of the box, produce some very nice daylight illumination for us. And if I just open up the asset editor and come to the GI controls we can see that when using those defaults we are working with brute force as the primary ray or primary light bounce engine whilst light cache is set up to take care of the secondary bounces. The problem we may run into with this setup on an interior such as this though is the fact that we're getting a really clean render, but even when using very simple materials, can be quite a time-consuming process. Although, of course the addition in recent years often has the tools to V-Ray, faster computing hardware, and of course the V-Ray cloud makes it easier than ever to accomplish. Assuming that we don't have the time or computing resources available to us on a project, though, let's focus on what we can do with just the irradiance mapping engine. There are a few tweaks that we will want to make to the default render settings before we go ahead and make any GI changes. So, let's jump into the render rollout and make the switch over to using booked rather than progressive base rendering. And then in the camera rollout we will want an exposure value of 3 with the related color mapping controls using a burn value of 0.2. For our output resolution, let's punch in values of 1200 by 675. And then finally, in the quality controls, let's set a max subtive sampling value of 25. All of those changes when we take a render producing this result. To start working with just the irradiance map system then, let's in the global illumination controls set the primary ray engine to irradiance mapping whilst also setting the secondary bounce engine to none, meaning that any light we now have bouncing around in the scene will be coming just from the default irradiance map settings alone. If we take a render, then, we can see how the irradiance mapping system works. Now, as V-Ray initially runs through an irradiance map path for us and then produces the finished render. Now, one of the nice things here is that we instantly get to see the irradiance solution as it is being calculated, meaning we also instantly get an opportunity to evaluate lighting and exposure levels, and if they aren't really working for us, we can quickly cancel the render, make some tweaks, and then render again. Now, clearly, what we currently see in the frame buffer window is a blotchy solution that really won't work for a final production render. The question, of course, is how do we go about improving the look of an irradiance map solution? Well, as we are using a mapping system, specifically, in this case, a 3D volume map, why don't we try increasing its resolution? Just as we might if we had a pixilated bitmap in a texture. This being something that we will look at doing in the next exercise.

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