If you've ever been frustrated that the mr Area Omni & mr Area Spot lights emit light as though they are point lights, this tip is for you. If you don't know what I'm talking about, hopefully the following info will help explain it.

Example: If you add a mr Area Omni light to your scene and then set the type to Cylinder in the Area Light Parameters roll-out of the light. Then set the height to something rather large like 60" or more and of course you'll need to enable the 'Show Icon in Renderer' option to see this...now render.

You'll get a result like this (click to enlarge)


Notice how the light is emitted from the center of the cylinder instead of along the entire length of the cylinder shape? That's the problem that I'm referring to.

Now, if you assign a light shader to the mr Area Omni, it will emit light evenly along the entire length of the cylinder:

After assigning a light shader (click to enlarge)


Here's a simple animation using this technique:
http://jeffpatton.net/Temp/Animated_lights.mov (right click, save-as)

Words of caution:
Keep in mind that when you assign a light shader, it affects how photons are emitted. So this method probably isn't a great idea for scenes where you use GI or Caustics...but for FG only scenes it can be useful.

Also, generally speaking you should normally use photometric lights in your scenes instead of the standard lights or the two mental ray area light types. YES, photometric lights work with mental ray and provide the most realistic results, provided your scene is modeled to a proper scale.

I've added a few more materials to my .mat collection here. There are two new carpet materials: The carpet-bump version works well for flat carpet/rugs, while the displacement version will provide a higher depth to your mesh for more plush carpet/rugs.

A&D carpet materials (click to enlarge)


Notice there's a third version there, the "grass-O-matic" version. Just wanted to show how useful that plugin is for things like carpet & grass, and YES, it works with mental ray just fine. You can download the free plugin from http://maxplugins.de/

Another simple grass-O-matic example:
http://jeffpatton.net/Temp/Grass_01.jpg
http://jeffpatton.net/Temp/Grass_wire.jpg

I've also added the following wet pavement material to the .mat collection. In the material editor it may appear rather complex, but it's not. It's basically just a blend between two A&D materials, one 'wet', and one 'dry'. You'll probably want to use your own asphalt bitmap since I just used one of the default maps that ships with 3dsmax.

Wet Pavement material (click to enlarge)


Here's the download link to my .mat file:
http://jeffpatton.net/Blog-images/J...r-materials.zip

And finally, no...I have not forgotten about the second installment of my parti-volume document. I have a little more research to perform before I finish the document. For now, here are a few volume caustic renders from my test scenes (that I may include with the document):

Volume Caustic Sample 01 (click to enlarge)


Volume Caustic Sample 02 (click to enlarge)


Volume Caustic Sample 03 (click to enlarge)

If you're using logarithmic exposure control with mental ray and finding your texture bitmaps a bit washed out, then you may find this tip useful.

As the help files in 3dsmax state, you should use EITHER logarithmic exposure control OR an adjusted gamma, but not both together. But, when using the logarithmic exposure control I've found that my bitmap textures will often look washed out or lack contrast. As it turns out, the logarithmic exposure control is "acting" a bit like an adjusted gamma setting. Therefore, I realized that if I used an adjusted bitmap input gamma setting, I can get the contrast/color back in my bitmaps when using the logarithmic exposure control.

Here's some additional information to help clarify the method:

Logarithmic Exposure control with default gamma settings (click to enlarge)


Logarithmic Exposure control with an adjusted bitmap input gamma setting (click to enlarge)


As you can see in my controlled environment test scene, a bitmap input gamma setting of 1.6 seemed to work best on my monitors here. Keep in mind that you may need to use a different value for optimal results on your own monitor(s).

I'll provide the test scene I used above so you can quickly explore what value works best for you. You'll probably find a range between 1.4 and 1.8 works best, here's the test scene:
http://jeffpatton.net/Blog-images/Gamma_start.zip

IMPORTANT NOTE: I forgot to mention that due to a display issue, it's best to restart 3dsmax whenever you modify the gamma settings. If you don't there's a chance that it will not display the changes properly.