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betty

mantra - renderman

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for people who are deeply into mantra,

is mantra and renderman similar enough where a book like 'advanced renderman' and its companion book would be a vital source for study. or would the way to go simply be from the help docs and study the VOPs networks that make the current default VOPs.

i just want to get better with rendering ( w/mantra ) and just wondering what is out there to assist me.

thanks

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Though not all of the code will transfer 1:1, the techniques explored in this text would definitely be useful. SESI provides an include library for doing some runtime translation of Renderman SL to VEX as well though I'm sure the more complex the shader the less likely this will work without modifying the code at least somewhat.

The help docs are an okay reference list of the commands available but they give few practical examples of how to put the commands to use. And some of the newer, advanced functions, like Image3D, are hardly documented at all, if at all. You'd most likely learn more by disecting the supplied shaders for what they DO show in a practical sense as well as the work of other Houdini enthusiasts posted on this site or linked to this site.

The two Musgrave, Worley, Perlin, et al texts on advanced Texturing and Modeling (or is that Texturing and Rendering?...mine are in storage and it's getting late, sorry) would be a good reference as well.

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I'm not an expert by any means, but I have read Advanced Renderman and the Companion. Much of what you learn in those books is directly applicable to Houdini. The concepts are very much the same, and the mathematics primer and explanation of the graphics pipeline in Advanced Renderman went along way toward clearing up my foggy notions of what 3D graphics was all about. As far as shader writing, the code won't transfer directly, but the concepts can easily be adapted to creating shaders in Vex or Vex Builder. The Companion is pretty terse, and somewhat specific to Renderman, but Advanced Renderman is very worthwhile to Houdini/Mantra users, and I imagine this upcoming Renderman crash course book will be useful as well.

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hey betty, if you want to take a look i can scan and send you a chapter or two. Let me know. Still there's a whole lot of good food for the brain in the siggraph papers from renderman.org, here and many other places. Maybe a bit more disperse but just as good.

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this sounds promising. basically wanted a guide to help me build shaders in VOPs and actually understand what i'm doing. also to help me with rendering efficiency. actually started to get some nice renders with mantra but quickly hit a wall, and have had a lot of problems with very slow renders when doing raytracing and displacements. i know it is getting a real workout at the moment in some films which sounds great so i'm sure the capabilities are there, i just have to learn them. all the other general info in the book will help in this way i guess........i just picked up digital lighing and rendering to help me with basics.

was talking to architects and realise there seems to be some work out there for 3d in this field, modeling with the main thing being the lighting and rendering so just plan to learn more.

also looking forward to v6, i'm hearing radiosity...sounds interesting.

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digital lighting and rendering is a GREAT book...(I think someone nabbed mine...I can't find it anywhere :angry: )

it gives some very good advice on lighting, something that's far more powerful than most people realize (the Advanced renderman bood also has a good chapter on lighting theory).

a guy I went to school with is doing architectural (sp?) stuff for the past year...check out the web for eg of renders using a - now discontinued - AutoDesk product called Lightscape ( http://www.ictech.ca/3Dsoftware/Lightscape_data.htm among others)

some very nice stuff...you could input the actual kind of lightbulb into lightscape and it would light the scene properly...

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...and for finding a good source of shaders to disect and play with go to:

http://www.renderman.org/RMR/

(ok, so they're all prman, so what? ;p)

and try to start with the simplest ones....it's all about divide and conquer.

another cool one to get into procedural textures:

http://www.accad.ohio-state.edu/~smay/RMan.../rmannotes.html

and last (should be first) but by no means least, our own good ol' Jason's tutorials on odforce itslef (remember, it's more than the forum) ;P

http://odforce.net/tips/ (7th and 9th topics)

you even get an i3d primer!

guess THAT shoudl get the ball rolling :D

Cheers!

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thanks everyone.

and of course the odforce shader tutorials were the first ones i went to, but only ever did the i3d ones. i recall running from the others when i first saw them but now will go again and try and take those into VOPs. actually a couple of days ago i was doing a fair bit with i3d with tips from jasons tutorial and got really great results after some tweaking.

thanks again

i'll chase these up, and dig deeper in VOPs

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If you wanna write shaders for Mantra, I'd suggest starting with VEX rather than RenderMan. RenderMan's language is very C++ like, but VEX is (in my opinion) easier to learn and, by the way, is a good way to start with RenderMan.

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@Stremik: Are you for real??? I always believe it's the other way around, tho...

Well...

I read "RenderMan companion", tutorials from web, disected shaders and yet couldn't make any sence of it all.

Not to mention that documentation that comes with RenderMan is crappy as hell!

With VEX it was all the other way around. Even tho there was fiew sources offering some info about VEX, I was able to write compile and test my very own shader 15 minutes after I started reading VEX help file.

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he he he....take another look at prman now, go ahead...

I just started to play with prman, after messing around with vex, and I have to say (so far), except for the syntax difference, they're the closest 2 languages I've used. let's just say that VEX is less fussy about type casting....

differences (for the shader writer) are skin deep. for instance in VEX you only need a vector for everything whereas in prman you have "point" "vector" and "color" types.....let' s just say that VEX is easier and rman in safer (I'm NOT arguing which is "best", ok? :) )

but they're fundamentally the same, dealing with the same concepts... both closer to C....

Are you sure you're not talking about RIB files? (the prman equiv. to IFDs...scene descr. files...)

those still don't look like C++, but they sure can get confusing ;)

....IMHO

regardless shading is possibly one of the coolest areas of CG, add lighting and serve hot!

Cheers!

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My bad! It's "C" like. You right.

Yes, I meant the RIB files which, I understand, I wouldn't have to write by hand anyway, but still. VEX is more "script" like and for someone who never done real coding before, is a lot easier to learn.

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