From the course: V-Ray Next for 3ds Max Essential Training

Using Light Cache - 3ds Max Tutorial

From the course: V-Ray Next for 3ds Max Essential Training

Start my 1-month free trial

Using Light Cache

“

- [Instructor] In this exercise we are again going to work with our interior scene in order to create yet another GI solution only this time using the Light Cache engine. The first thing that we will want to do then with the render setup dialog open is set Light Cache as our primary ray or primary bounce engine whilst once again setting the secondary dropdown to none. Now whilst the default Light Cache settings, as with the radiance mapping, are designed to give us a fairly decent level of quality from the system right out of the box. The simple truth in this instance is that the settings are assuming that we will be using Light Cache in it's preferred or recommended role as a secondary bounce engine. If we go ahead and take a render then, we will instantly see a couple of interesting things happen. Firstly, we get a really high level of illumination in the render, certainly much brighter than was the case with our radiance map solution, which happens because Light Cache rays automatically perform multiple light bounces in a scene, as opposed to a radiance mapping's single bounce. And they do so very quickly indeed, which is possibly the biggest strength of the Light Cache technology. We also see though that, even with a reasonable default subdivision value of 1000 set, we are getting a very soft looking render indeed. Mostly because Light Cache has been designed to bounce light around an environment as quickly as possible, and so isn't too interested in things like contact shadows. What about coming to the Light Cache controls then, and increasing the subdivision value? Surely, more samples will equal more quality. Well, let's try a significant jump and go all the way up to 5000, keeping in mind here that in terms of actual samples or rays being used, this value should really be read as 5000 samples multiplied by 5000 because a subdiv number in VRay is the square root of the actual sample or ray count being used, meaning we are now producing a total of around about And yet, even so, if we save what we have and take another render, we can see that, whilst what we get does look a little better, in terms of noise and shading, and still doesn't take much time at all to render considering we are using such a high sample count, we still couldn't use this lighting solution in any kind of a deliverable final render. Let's go crazy then and set a subdiv value of 10,000 Where the result shows that the simple, and yet, inescapable truth, is that the Light Cache engine just wasn't designed and so isn't really a particularly good choice for use in the primary engine slot, given that the solution's it produces are both soft and generally speaking quite blotchy, even when using very high subdivision counts. Let's move onto our next exercise then Let's move onto our next exercise then and take a look at how the brute force engine will fare in this same indoor setting. will fare in this same indoor setting.

Contents