Dirtmap And Zdepthdof

[JohnnyBGoode]

Hello to all the helpful at Odforce

i'm back again..

Just wondering....

Is there anything similar to the Dirtmap shader for Mental Ray that is available for Mantra or able to be built in Vops to be equivalent ?

From what I hear the dirtmap shader is often used in industry.

I dont know too much about it, ive never used it for Maya, but it does sound really cool.

Actually...while im on the subject of cool shaders, has anyone checked out the ZdepthDOF shader by Andreas Bauer?

Andreas is my classmate here at Bournemouth, (he is studying the MSc), however unfortunately he doesnt use Houdini extensively and now that we have started our masters projects, he hasnt got the time to set it up so that it is useable with Mental Ray in Houdini.

I dont know if anyone would be interested in taking him up on the offer of doing that so that we could use it - or even construct one for the Houdini exchange?

I'm not really a shader writer myself, so I wouldnt really know where to start or have the time to dedicate to learning right now...but its a great idea.

I know that if I just composite in Halo, I could render image files with depth info anyway, but it would be great to have something like this when im working in Shake - especially for Mantra too, as I tend to use this as my renderer.

What are peoples thoughts/advice/ideas?

J

[Jason]

I don't have much time for a full answer, but an interesting and FAST approach to getting dirt into nooks and crannies is to do something like the autovc trick described in the following OTL available from the Exchange:

http://www.sidefx.com/exchange/info.php?fi...4&versionid=194

[AdamJ]

Dirtmap seems to be an ambietn occlusion shader so you can use the same in VOPs, the occlusion VOP. You can also try the occlusion shader that Jason posted that uses point clouds so it's faster than brute force raytracing.. you can find the shader pack in this thread (it also includes a cool lighting SHOP and a subsurface SHOP !!)

http://odforce.net/forum/index.php?showtop...35&hl=occlusion

As far as the zdepthDOF I attached a hip file with a VOP shader that will let you output different RGB passes to be used for post DOF. You can choose the camera range for the effect of the shader, set the gradients for each channel and render all of them as one image or seperate. Have a look..

zdepthDOF.hipnc.gz

[JohnnyBGoode]

Jason - Cheers, ill have to check it out.

I should have been a bit clearer though, in that the reason im after the 'dirtmap' shader is that as far as i know it is used as a way of faking ambient occlusion and IBL.

I have attached an htm document and accompanying jpgs that come with the dirtmap shader explaining how it works and what it actually does (sorry this is how document is given with the shader).

AdamJ - THANK YOU SO MUCH. That Zdepth is really really cool and useful! Also thanks for including the .hip file so I can see how it was constructed. Its a bit tricky to use, but im sure with a bit of play i will work it out. So so cool - did you construct this yourself?

One thing - you mentioned i could just use the occlusion VOP to make a shader, would this really be similar to the dirtmap shader and produce faster results like the dirtmap document I have attached suggests?

Those shaders that Jason posted are really cool - but i cant work out how to use the fastgi. How does it need to be lit, or setup to approximate the look of Ambient Occlusion?

dirtmap.htm

[JohnnyBGoode]

Those shaders that Jason posted are really cool - but i cant work out how to use the fastgi.  How does it need to be lit, or setup to approximate the look of Ambient Occlusion?

19205[/snapback]

ok - i worked it all out from another post and the fastgi is so so cool.

Cheers.

J