New Mental Ray grass displacement tutorial

[pixelperfectg]

Since the existing grass shader on my site is starting to show it's age, I thought I would share one of my more current methods of displaced grass. Here's the link: http://jeffpatton.net/MR_Grass_displacement.htm

[TheAllusionist]

Thanks for sharing, a pretty sweet effect for a common need in Arch Viz

[nisus]

Tnx Jeff,

Do you know about a limit of how large the surface can be with your grass?

Have you experimented with depth falloff to save rendering time on not having to displace at larger distances?

rgds,

nisus

[nisus]

Hi Jeff,

I've checked your new tutorial. It looks great and simple.
I have a question about your render settings though.

Why do you set FG max and min radius to the same value? I've read that these should be 10x apart, basicly 1/10th and 1/100th of the scene diameters.
What are your findings upon these values/rules of thumbs?

rgds,

nisus

[pixelperfectg]

Originally Posted by nisus

Have you experimented with depth falloff to save rendering time on not having to displace at larger distances?

Yes, at times I use various materials to control where displacement occurs on large objects. No sense in having a displacement calculation when it can't be seen (behind objects), or won't be noticable simply due to the camera distance.

Originally Posted by nisus

Why do you set FG max and min radius to the same value? I've read that these should be 10x apart, basicly 1/10th and 1/100th of the scene diameters.

As I briefly mention in the tutorial, the settings I used are just for simple/fast preview renders. naturally, the FG won't be super accurate, but for testing, it works well. And since I really only needed a touch of skylight for this scene I just left the FG at my test values.