LuxRender 0.8-dev – Velvet and Surface asperity

Since LuxRender 0.7 came out a while back, there has been a steady push into the next instalment of Lux. While we are due a bugfix release 0.7.1, which looks just around the corner, I am going to check out LuxRender 0.8-dev

Thanks to some tinkering and planning, LuxRender can now be compiled from source straight from the box, without too much effort. Previously, because of dependancies not all working on OSX without some serious work, it was somewhat difficult to produce working binaries. With 0.8, the dependancies have all been precompiled and provided by Jens (Thanks, you are a legend).

Starting with CMake 2.6 it is possible to produce an xcode project and have xcode compile and link everything. From the LuxRender forum the procedure goes as follows (for luxrays and luxrender)

Get luxrays,macos,lux source from the luxrender repository uncompress them into the same folder.

Compile LuxRender(OSX 10.6)
Get QT 4.6.3 or higher and install it.(if not done yet )
In cmake ( 2.6+ recommended ), choose :
1. configure -> xcode-crosscompile
2. set in crosscompile: Name = darwin, version = 10.6, Processor = i386, x86_64, c = gcc, c++ = g++, root = /Developer/SDKs/MacOSX10.6.sdk
… Modes = set all to “find from root then native system”.
press configure once more , then boost is found in boostroot
3. generate
4. open XCode.project
5. set wished arcitectures to build ( default = 2 arch universal Intel )
6. build

Only thing to make sure of is in xcode is to set it up as an xcode 3+ compatible file, and select the correct version to compile… (that is, release rather than debug or anything else) Hitting build should make it compile just fine.

Now for the experiment!
The current version of LuxRender 0.8 does include some GPU acceleration, however it is very very early stages and for now I am going to wait until it is a little more stable and less memory hungry. For this experiment i am going to test the velvet material, the surface asperity option in the glossy material and learn about the Blender cloth sim.

For the scene I wanted to have some cloth folded over in a corner to provide me with a background that isn’t just flat and featureless. This is were the cloth sim comes in!

We start out by making a corner ledge like setup.

The purpose of the bumps is to give the surface of the cloth on the bottom some features rather than just being totally flat. Now, we go to the Physics options in blender and set everything to provide collisions. Above this i added a plane. I subsurface this 12-13 times and set the mesh to be rendered smooth.
After this in the Physics options i selected cloth, and turned on self collision, and hit bake. After watching the sim drop the cloth over the edge, i stopped it when the desired shape was reached.

So far so good!

Next I simply set the materials of the scene (I also added an old lightbulb model for the render) I left everything on defaults and added some mesh lights. I pointed the LuxRender 0.8 exporter at my freshly compiled version of Lux and hit GO!

Here are a few tone mapped examples with different lighting. Which show off the new material. For your comparison there is a glossy and matte render also.

As you can see, nice and velvety, it is mainly shown by the bright edge at glancing angles and the dark shadows.

Next up is the surface asperity.

And finally – for Matte

My thoughts on this exercise is that for cloth, maybe the gloss with the asperity option selected gives a nicer result. However if something definitely needs to be velvet then it too gives a great effect.

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This entry was posted in Blender, LuxRays, LuxRender. Bookmark the permalink.

One Response to LuxRender 0.8-dev – Velvet and Surface asperity

  1. Knusbaerli says:

    Great illustration of the new velvet material. Thanks

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