Join Brian Bradley for an in-depth discussion in this video Generating the caustic effect, part of V-Ray 3.0 for 3ds Max Essential Training.
- Although we have, up to this point, in our exercise, run through some essential scene setup and have even enabled Caustic Generation in our scene, we aren't currently, if I go ahead and take a render here, getting any Caustic showing up. Now, if we're coming to V-Ray in 3ds Max as a Mental Ray user, we may wonder whether or not our geometric objects need to be told to specifically act as Caustic Generators in the scene, as they do in Mental Ray. Well if I just select our Butterfly Geometry here, and then right click and go to V-Ray properties, you can see in the dialogue that appears, that our objects are set up by defaulting V-Ray to both generate and receive Caustics, as indeed are all lights.
The first problem we need to tackle then, is in fact a material-based one. So let's open up the Material Editor, and in the Glass tab, double-click to access the butterfly material's properties. Down in the Refraction section, we have two options that are currently contributing quite significantly to what we are seeing in our render here. One is the Fog color, that is creating the deep burnt orange look of the glass itself, and the other is this Affect shadows option. This is allowing the refractive properties of the material to create the colored or transparent orange shadow effect that we are seeing.
If I just turn that off, and then re-render, you can see that we now have regular, opaque shadows instead. This is how we need our material to be set up in order for a Caustic Effect to be generated. How is it, then, you may be asking, that we aren't seeing Caustics in the render right now? They are, after all, turned on in the scene. Well, there is one more piece of scene set up that needs taking care of, which is to optimize our V-Ray sun's position in the scene.
Now obviously, if we have carefully set up the lighting for our shot already, the last thing we will want to do now is go ahead and disturb our sun's orientation. Because positional information for the Compass Rose, though, doesn't affect the sun's orientation in the scene at all, this isn't going to be a problem. Let's select the Compass Rose from our Layer Manager, then, and from the main tool bar, select the Align tool, click the Butterfly Geo in the viewport, and then, with the X, Y, and zed, or Z position, and Pivot Point to Pivot Point options enabled, click OK.
Let's save the render we have to our History list, and again, take a test render. What we straight away, even in just the light cache pre-calculation, is that we now have a very clear Caustic Effect showing up in our scene. Indeed, if I lowered our previous render into Channel A, you can see as we make a comparison, that even though we aligned our Compass Rose to the Butterfly Geometry, the orientation of shadows in the scene, in fact, the lighting in general, hasn't altered at all. Which means, the only thing we need to do now, is refine our Caustic Effect.
If we wanted to brighten the Caustics being created in our shot, without affecting the intensity of the light object being used to create them, that is, we could come back to the Caustic controls in the Render Setup dialogue, and in the Advanced UI mode, use this Global Multiplier option. The problem with a Global Multiplier, of course, is the fact that it is, well, global. What if we have a few Caustic Generating objects in our shot, but only really needed one of them to be brightened. Well, we could instead choose to handle this, by revisiting the V-Ray object properties dialogue, and instead, make use of this Local Caustics multiplier option.
As I am, in fact, more than happy with the brightness of our Caustics, though, I'm just going to close this dialogue, and focus instead on sharpening our Effect up a little, as the edges of the Caustics do look a little soft to me. This, though, is something that should be done judiciously, as, unlike brightening, we can add quite a bit extra to the overall render time as far as shot. To show how this can be done, though, let's open up the V-Ray Light Lister tool, and increase the Caustics subdivs value for the Sun002 object, to 6000.
If we close the Light Lister, save our current render, and then take a new one, we can see, as we compare the two images, that we're now getting a much sharper, cleaner look to our Caustics. Of course, we have added quite a bit to our render times, and if we were rendering the entire scene, perhaps with even more Caustic Effects, things would slow down even more. That having been said though, seeing as we have been able to create a very nice refractive Caustic Effect in V-Ray, with very little effort at all, I would say the increased render times are well worth the wait.
- Using the new UI elements, Quick Settings, and revamped Frame Buffer
- Understanding color mapping modes
- Adding V-Ray light types
- Working with the V-Ray Sun and Sky systems and dome light
- Using irradiance mapping and light cache
- Working with diffuse color maps
- Making reflective materials
- Creating a translucency effect
- Using the new SSS and skin shaders
- Ensuring quality with image sampling
- Working with the adaptive subdivision engine
- Controlling the physical camera
- Working with FX tools such as VRayFur and VRayMetaball
- Stereoscopic 3D rendering
- Using Render Mask
Skill Level Intermediate
Q: This course was updated on 02/02/2016. What changed?
A: We added tutorials on the new 3ds Max camera tool, which replaces the defunct V-Ray Physical Camera. The author also includes a method for creating a V-Ray camera via scripting.
Q: This course was updated on 04/19/2018. What changed?
A: New videos were added that cover V-Ray 3.1 to 3.3 updates.