Full Cook-Torrance model #6752

New Issue

Tom Bech · 2007-05-26T14:18:44+02:00

Tom Bech commented

2007-05-26 14:18:44 +02:00

%%%Hi!

I'm new to Blender, so bear with me :)

I noticed that Blenders Cook-Torrance (CT) specular shader isn't really a "true" CT BRDF model as it lacks it's microfacet base. I'm not sure why it's designed this way, but sometimes it's useful to be able to specify the "standard" set of parameters for a CT model, for example when trying to reproduce the results from tutorials for other programs or from a research paper.

I've written a "full" CT model (see diff's attached) for those who might be interested in this kind of thing. It's a pretty trivial piece of code, and I'm not even sure if it's of interest to anyone else but me :)

I don't know Blenders code well at all - for example, where does the export to yafray occur? I've only modified the shader panel and the file DNA and the shader code, but I'd like to be able to export the "full" settings to yafray as well.

Tom%%%

%%%Hi! I'm new to Blender, so bear with me :) I noticed that Blenders Cook-Torrance (CT) specular shader isn't really a "true" CT BRDF model as it lacks it's microfacet base. I'm not sure why it's designed this way, but sometimes it's useful to be able to specify the "standard" set of parameters for a CT model, for example when trying to reproduce the results from tutorials for other programs or from a research paper. I've written a "full" CT model (see diff's attached) for those who might be interested in this kind of thing. It's a pretty trivial piece of code, and I'm not even sure if it's of interest to anyone else but me :) I don't know Blenders code well at all - for example, where does the export to yafray occur? I've only modified the shader panel and the file DNA and the shader code, but I'd like to be able to export the "full" settings to yafray as well. Tom%%%

Tom Bech commented

2007-05-26 14:18:44 +02:00

Changed status to: 'Open'

Nobody commented

2007-05-26 14:18:44 +02:00

Changed status from 'Open' to: 'Archived'

Nobody closed this issue

2007-05-26 14:18:44 +02:00

Tom Bech commented

2007-05-26 15:08:41 +02:00

%%%
Sorry - I found the yafray exporter, didn't realise it was in cpp files. Seems yafray replicate the blender shaders so I guess I must implement the CT shader in yafray as well if I want it.%%%

%%% Sorry - I found the yafray exporter, didn't realise it was in cpp files. Seems yafray replicate the blender shaders so I guess I must implement the CT shader in yafray as well if I want it.%%%

Tom Fitzgerald commented

2007-09-10 22:02:30 +02:00

%%%Hi

I am interested in implementing "physical" brdf models also. Please contact me to discuss is you are still interested. my email is tomfitzrugger@gmail.com. I am completing a PhD scene visualization project and am struggling with how best to put my "shaders" into blender.

Thanks

Tom%%%

%%%Hi I am interested in implementing "physical" brdf models also. Please contact me to discuss is you are still interested. my email is tomfitzrugger@gmail.com. I am completing a PhD scene visualization project and am struggling with how best to put my "shaders" into blender. Thanks Tom%%%

Tom Musgrove commented

2007-12-09 17:25:02 +01:00

%%%perhaps brecht can have a look%%%

Brecht Van Lommel commented

2008-07-10 18:19:24 +02:00

%%%I'm reviewing this one now, better late than never.. But I'm still trying to figure out how this fits with other specular shaders, to avoid overlap, it's a bit ugly to have a Cook-Torrance shader and a Full Cook-Torrance shader, ideally there would be only one with more settings, but this works quite different from the existing one. There's also this beckmann shader patch, not sure how it fits together:
http://projects.blender.org/tracker/?func=detail&aid=11747&group_id=9&atid=127%%%

%%%I'm reviewing this one now, better late than never.. But I'm still trying to figure out how this fits with other specular shaders, to avoid overlap, it's a bit ugly to have a Cook-Torrance shader and a Full Cook-Torrance shader, ideally there would be only one with more settings, but this works quite different from the existing one. There's also this beckmann shader patch, not sure how it fits together: http://projects.blender.org/tracker/?func=detail&aid=11747&group_id=9&atid=127%%%

Ton Roosendaal commented

2008-09-18 19:10:39 +02:00

%%%I propose to postpone this, and make it part of the new shader system we want for Blender.

Also a note: I did the Cook Torrance, and removed the nasty parts that took far too much rendertime and were nearly visible. Scientific accurace was not a spec for Blender really. This is better off as an option for a flexible shader system.

Thanks nevertheless, good reference for us.%%%

%%%I propose to postpone this, and make it part of the new shader system we want for Blender. Also a note: I did the Cook Torrance, and removed the nasty parts that took far too much rendertime and were nearly visible. Scientific accurace was not a spec for Blender really. This is better off as an option for a flexible shader system. Thanks nevertheless, good reference for us.%%%

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Full Cook-Torrance model #6752