Stmap/idistort

[lebedev2]

After reading the last post and being somewhat new to NUKE and 3d comp in general can someone please explain a real world situation of how they used either of these two nodes and a generalized idea of work flow.

Can I use a bent normal pass out of mental ray and shuffle it into the uv parameters to then perturb the rendering 3 dimensionally. Any ideas, pointers or help here would be greatly appreciated.

s

[sithwarlord]

if you are using bend normal you don't want to use uv channels since they only represent two colors
or basiclly your x and y direction. but you could shuffle the channels with ShuffleCopy or ChannelCopy in your flow anyway and then you are able to use all 3 of them eg. N.x N.y N.z
than you can do lighting and so on
hope that helps

cheers

[maya-man]

You can use STMap to do a UV warp of a texture based on the red and green channels of the (bent) normals, yielding a cheap image-based illumination...you would blur the texture before the STMap to mimic diffuse convolution.

AFAIK the correct format for the texture is a mirrorball-format lightprobe. Blue (z) in the normals image is ignored but it's contribution is "implied"....at least, this is my understanding of it. Also, I think the normals should be in world space.

Michael

[lebedev2]

Hey if any could post screen grabs of their comps that could illustrate this particular work flow that would be great.

I would say that any good screen grabs of any well done comps would be very helpful in learning nuke. I have gone through all the D2 tut's and doc's, watched the DVD's, done every tutorial that I can/could find but there are a lot of gaps in the info out there that I think could be resolved with the help of the people that use Nuke by just posting some of the more interesting screen grabs.

s

[user_deleted]

QUOTE(sl0throp @ 11/10/06, 09:42 AM) [snapback]252118[/snapback]
Hey if any could post screen grabs of their comps that could illustrate this particular work flow that would be great.

I would say that any good screen grabs of any well done comps would be very helpful in learning nuke. I have gone through all the D2 tut's and doc's, watched the DVD's, done every tutorial that I can/could find but there are a lot of gaps in the info out there that I think could be resolved with the help of the people that use Nuke by just posting some of the more interesting screen grabs.

s

I put together a really basic tutorial on how to use the STMap or IDistort to texture an object based on it's UV data. It's kinda simple but might gives you a better idea. It's probably what Michael was talking about.
Maybe others are willing to share some workflow ideas as well?!
This site needs a few more tutorials anyway
http://www.fxshare.com/nuke/tutorials/gene...rkflow/292.html

cheers,
frank

[lebedev2]

This is exactly what I needed, thanks a lot. D2 could take some lessons from the people at SideFx and how they have those recipes that just show you how some of the nodes do a specific function or thing. A simple elucidation of a workflow and now you know it, because for the most part the manuals and tutorials are not very good and I am sure that they have access to some good screen grabs.

Jordan

[user_deleted]

QUOTE(sl0throp @ 11/16/06, 09:55 AM) [snapback]252592[/snapback]
This is exactly what I needed, thanks a lot. D2 could take some lessons from the people at SideFx and how they have those recipes that just show you how some of the nodes do a specific function or thing. A simple elucidation of a workflow and now you know it, because for the most part the manuals and tutorials are not very good and I am sure that they have access to some good screen grabs.
Jordan

Yes I agree. They have been working on updating the docs but at the moment they simply lack resources to make that a priority. From my experience though I'd say that this and other forums can take a lot of work of their shoulders in that regard so I encourage everyone to share their tips and tricks and write up the odd tutorial when they have a few minutes. Usually user based tutorials are much more valuable then the stuff that sips with most software packages since .

frank

[maya-man]

QUOTE(rueter @ 11/16/06, 02:19 PM) [snapback]252549[/snapback]
I put together a really basic tutorial on how to use the STMap or IDistort to texture an object based on it's UV data. It's kinda simple but might gives you a better idea. It's probably what Michael was talking about.
Maybe others are willing to share some workflow ideas as well?!
This site needs a few more tutorials anyway
http://www.fxshare.com/nuke/tutorials/gene...rkflow/292.html

cheers,
frank

Frank, thanks for posting your tutorial. Was the UV pass from prMan, ie. is this why the uv channels were in green and blue?
Yes this is the basic technique I was talking about, but you can substitute the UV render for a bent normal render to remap an environment image. I believe that the image has to be in mirrorball format, or it may be OK in spherical format, either way, when you know, you can change one to the other by using the environment map node. Also you have to blur the hell out of it to mimic a diffuse surface.

There is more info on this if you download the Siggraph paper "Lumo: Illumination for Cel Animation" by Scott F. Johnston

I could possibly do a tutorial but it's not that different from what Frank has done.

Cheers

Michael

[user_deleted]

thanks, I'll definitely have a look at those papers.
the uvs in the tutorial were a bit of a hack from 3dsMax.

I'm just playing with reflections myself and am using the xyz normals pass. haven't quite figured out how to prewarp the texture properly yet to mimic various environment settings in Max but I'm sure it won't be too hard.

go ahead and post your tutorial, better to have redundant ones than none at all!

frank

[maya-man]

QUOTE(rueter @ 11/21/06, 11:47 PM) [snapback]252939[/snapback]
thanks, I'll definitely have a look at those papers.
the uvs in the tutorial were a bit of a hack from 3dsMax.

I'm just playing with reflections myself and am using the xyz normals pass. haven't quite figured out how to prewarp the texture properly yet to mimic various environment settings in Max but I'm sure it won't be too hard.

go ahead and post your tutorial, better to have redundant ones than none at all!

frank

The eval is about to run out but I should have a full license soon...will see what I can do, and of course I expect someone to correct me if I do something wrong.

Michael