Blurry reflections and refractions are
normally hardly to achieve. One common way to do them with 3dsMax is by
using a very fine grain noise as bump map. This usually doesn’t give a
satisfying result, so this tutorial will give you a method to do (nearly)
correct blurred reflection and refraction in 3dsMax.
As we do not want to have the reflection
blurred in every raytraced material we use, we disable all settings we
don’t want to have (on a global level):
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This done, we switch over to the material
settings. Create a raytrace material and make it fully reflective. Assign
it to your test object.
Open the settings from the "…"-button.
Now disable the adaptive part of the antialiaser as it will cause artefacts.
To achieve this, set the threshold down to 0.0 and the initial and max
rays to 128. The value for initial and max rays heavily depends on the
amount of blur you are going to use (we use an amount of blur of 10.0 and
a defocusing of 1.0 in this example). So if your reflections look not as
smooth as they should, increase the value here.
Hit render and you should get a result
like in the following image:
Experiment with the blur and defocusing
amount to get the effect you are looking for.
Blurred Refraction (Frosted Glass) Blurred refraction (or frosted glass) will
be done in the same way like we did the blurred reflections. Again, enable
the global antialiaser and a raytraced material. This time, leave the reflections
set to zero but enable the transparency of the material. You can combine
it with reflection later but for now we only care about the refraction.
Assign the material and render:
This gives a nice blurry refraction, but
if we aim for frosted glass we need to add the effect of light scattered
inside the material. To do this, we will use "Falloff end distance" for
refraction in the raytracer controls:
This gives a result like this:
Using the map slots As you might have noticed, blurring and
defocusing both have map slots to control them. This gives you the ability
to control those parameters on a per-pixel basis from a greyscale texture.
[Grab the zipped tutorial here (282KB).] If you have any questions or comments about this tutorial, don't hesitate to contact me: shawn.hempel@useddishes.com Back
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