PDA

View Full Version : Can you get this to work?

azozel
01-12-2010, 12:49 AM
There is an old lighting trick in most apps where you offset the pivot point of a light ( usually a spot) slightly and spin it 360 deg ( or so) with motion blur on to get soft Gi like shadows. With enough of them you can even get better Gi results with less computation time. My question is how do you get it to work in max?
I have tried mental ray, Vray, & Scanline. The closest I have come is to render it with multipass camera and then it stutters and looks crappy.

http://forums.cgsociety.org/attachment.php?attachmentid=149651


I project this image out of a spot and give it a 360 deg spin with the axis offset slightly and set the pram curves to relative repeat.
Light turns purple = success.
Kev3D
01-12-2010, 03:16 AM
I've heard of the trick and I think it's specific to the scanline render. Correct me if I'm wrong but both Mental Ray and VRay have highly optimised GI and area light algorithms which means it takes far less time to achieve the same effect.
Rens
01-12-2010, 11:10 PM
It would probably work with vray motion blur (in the render settings > camera), but as mentioned, area lights would be faster.

If you're looking for a GI look with scanline you could also use several spotlights with soft shadow mapped shadows. Look up E-Light.
mister3d
01-13-2010, 02:38 AM
I've heard of the trick and I think it's specific to the scanline render. Correct me if I'm wrong but both Mental Ray and VRay have highly optimised GI and area light algorithms which means it takes far less time to achieve the same effect.
It's true about Vray at least. I sometimes don't use GI as a habit, and when my mate asks why if it takes so little time, I just stare blinking. :argh:
azozel
01-14-2010, 01:04 AM
if I can get it to work in vray with out Gi turned on I'd be ecstatic.
CHRiTTeR
01-16-2010, 04:43 PM
works fine here using the multi pass camera effect...

I did it in scanline but it should work just fine in vray.


http://img19.imageshack.us/img19/127/winug.jpg (http://img19.imageshack.us/i/winug.jpg/)


Although when i add an offset to the light's position the resulting light isnt even, but thats absolutely normal if you ask me (because the projection's patern gets offsetted).

http://img685.imageshack.us/img685/2466/offset.jpg (http://img685.imageshack.us/i/offset.jpg/)

Here's the scene:
http://www.speedyshare.com/files/20370789/Light-spin.zip
Be sure you render on frame 5 or the blur wont be centered/biased correctly.
CGTalk Moderation
01-16-2010, 04:43 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.