Thursday, February 21, 2013

Translucent Materials and Caustics

When I was modeling the Blu-ray Case, I tried to keep in mind the option of creating a translucent plastic material inside a 3D application using such renderers as Vray, Brazil, Iray... So I made sure
to construct the casing as a shell that was empty inside but still retained faces and volume much like a real Blu-ray Case. By doing this, It would allow artist to apply a translucent material to emulate the plastic seen on such cases. With the right lighting and Material settings, you can pull off a pretty convincing plastic look for the model.


For these samples, I used Vray materials, lights and renderer inside 3DS Max. Now this particular model as well as the DVD case included with the download, are UV mapped with multiple surfaces so that artists can apply different materials to different portions of the mesh for a more realistic look. In the case of the Blu-ray model, there are three material IDs( one for the sleeve, one for the casing and one for logo on the casing). Each ID was assigned its own Vray material which was attached to a multi-sub object material that was then assigned to the mesh. Each Vray material had its own properties making each portion of model unique and more realistic, in this scenario, I went for both reflective and refractive surfaces. The "diffuse" consisted of either a color or image depending on the surface. For reflections, I chose a dark grey for most surfaces. In Vray, reflections work by gray-scale  the closer to black= less reflective and closer white= more reflective. This is then further defined by a glossiness. Glossiness can be likened to clarity, a value of "1" will yield seemingly opaque reflections. As the value decreases so will the clarity of reflections and specularity will increase, introducing "hot spots". So basically a value of "0.9" or less will muddy up your reflections increase your highlights. Now refractions work very similar, however, they control the translucency of an object, like glass. But again, closer to black= solid and closer to white= more like glass. Glossiness again plays a big role. Same math but different results. value of "1"= perfectly translucent, value of"0.9" or less= denser more opaque. Playing with these parameters can be time consuming but needed achieve the desired results. Increasing the samples of each parameter will increase the quality but also the render time, but not by much.


The Scene was lit with three Vray lights, placed on the left and right of the scene for some edge lighting and then the third just out of frame directly onto the meshes as a soft key. The intensity will vary as in all cases, its  just something you will have to tweak and render until you get the results you are after. As an added effect, also included a Vray HDRI material applied to the environment settings in the render dialog as well as the caustics option. Caustics are a great addition to any translucent or refractive material. When added, is causes the light that is passing through the object to scatter and cast glare onto other surfaces and even small shadows within the refractive object. Consider it somewhat of a specular shadow-if that makes any sense... And the default settings gave me decent results, however the UI and setup may be different for each application(In Max, this does increase render time, as it requires its own calculations before beginning the render). So if you haven't already, download the free Model pack today, you can find it HERE. The file formats are available in FBX and OBJ, compatible with most 3D packages(Max, Maya, C4D, Blender, etc.) Including VideoCopilot's Element 3D for Adobe After Effects, presets included with download.

Software used:
3DS Max 2012

2 comments:

  1. Hi, don't know if you'll read this, but I found your blu-ray case freebie at TurboSquid and I had problems rendering it. I am a Poser user (I know... please don't poke fun) and I tried to render the case in Octane render, but the label part renders black. The blu-ray logo and case itself render fine. I tried reversing the normals and saw that the label then rendered half of it. What is weird is that I can see the blu-ray label texture I made in the preview fine... it just doesn't render properly. I tested this with both the quad and tri versions.

    I don't know if you use Poser, or might have an idea how to fix this. This freebie is just too good to pass up and I'd love to get it to work in my scene! Thanks!

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  2. Sorry about the late reply and rendering issue, i will look nto this asap, was this with the obj and fbx or both?

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