Symbolic Posted April 24, 2007 Share Posted April 24, 2007 Hi, I am experimenting with the Camera Projection Techniques. Most of the resource are for Maya and Max. I am trying to understand what is going on, then trying to translate the information for Houdini and apply it there. I know that most of the Houdini resources are for DOPs and POPs and procedural things...(And I have spent my last 7 months exploring them)... I do not want to split my workflow and go into Maya for that... so I want to explore the issue from the Houdini's point of view. The issue is actually quite diverse. It has relations with "Image Based Modeling (Photogrametry)" and things like that. I also know that there are lots of papers on that and I am planning to get into them... But before that... Maybe some of you have had experience with this issue inside Houdini... // Here are some results from my experiment: test1X.mov This is how the Houdini scene looks: These are my two different photo segments that are projected on two different geometries: // There are issues. Since there are two different images and tow different geometries... I do not know how to make them overlap properly. I know this is not a Houdini specific issue. I am just asking of advice and some suggestion on resources. Thanks. Quote Link to comment Share on other sites More sharing options...
lynbo Posted April 25, 2007 Share Posted April 25, 2007 We have done alot of this kind of thing for a specific client that we have and in this case it is probably best just to "paint in" the needed parts. This is of course if it is a static image, if it is to be footage then you will want to go a comp route. See www.janimation.com look in the portfolio section for the Chick-fil-A "cows in shining armor" and "the good the bad the hairy" These spots take the hi res imagery that is used in their calendar. (very funny) We take those and turn them into a spot using almost entirely camera projection. When we get to a place like you have in your example we go into 3d paint and add what we need. HTH -Lyn- Quote Link to comment Share on other sites More sharing options...
Symbolic Posted April 25, 2007 Author Share Posted April 25, 2007 Thanks! Hi, The problem with my camera projection is that: I have one projection camera called "Projector_Camera". Whenever I have a problem... I create a secondary camera called "Patch_Camera". With this Patch_Camera... I go and look at the problematic area... render a frame (1000x1000 px)... paint in a fix for the problem... then project the fixed image through the Patch_Camera... So I have two projections now... But when I render the scene from my "Viewer_Camera"... I notice the artifacts at the locations where both projections overlap... The patch has an soft edge... Alpha Channel that is supposed to help it blend better... But it is not blending... And it seems like Houdini is not rendering that Soft edge at all... there is always something "white" under... I will try to post some videos in order to illustrate the problem. Quote Link to comment Share on other sites More sharing options...
symek Posted April 26, 2007 Share Posted April 26, 2007 Render these texture layers separetly and compose after. Don't use alpha channel of secondary texture in shader since you cut off your projection too early, export alpha as another layer and with these three passes (first proj., second and mask for mixing) you can easier handle your task in post. does it make sense? Quote Link to comment Share on other sites More sharing options...
Symbolic Posted April 26, 2007 Author Share Posted April 26, 2007 Render these texture layers separetly and compose after. Don't use alpha channel of secondary texture in shader since you cut off your projection too early, export alpha as another layer and with these three passes (first proj., second and mask for mixing) you can easier handle your task in post.does it make sense? Thanks! This makes sense... but I am not able to composite the secondary texture because it is spreaded and multiplied all around... Quote Link to comment Share on other sites More sharing options...
Symbolic Posted April 26, 2007 Author Share Posted April 26, 2007 (edited) This is how it looks: The view through the "Patch Camera"... I have added an element to the render from that camera... and projecting it back... But it is all over the geometry when looking through the other cameras... so it gets rendered... I know that I can select only some of the faces to receive the projection... but is there another solution... I think I have to do it with different passes... like... back + patch and "clip matte(s)" this is the problem. The PATCH CAMERA: The VIEW CAMERA: Edited April 26, 2007 by Symbolic Quote Link to comment Share on other sites More sharing options...
stu Posted April 26, 2007 Share Posted April 26, 2007 Looks like it could be a pre-multiplication problem. Did you make your own shader or are you using something that shipped with houdini? Quote Link to comment Share on other sites More sharing options...
Symbolic Posted April 26, 2007 Author Share Posted April 26, 2007 Looks like it could be a pre-multiplication problem. Did you make your own shader or are you using something that shipped with houdini? No... No... This is just the crappy openGL... I already gave up the idea to be able to combine the two projections in Houdini... What I want to do now is render the patch separately... But it is all aroyund my geometry... I am not able render it only where it should be Quote Link to comment Share on other sites More sharing options...
old school Posted April 27, 2007 Share Posted April 27, 2007 You may want to try the option in the viewport dialog option > Misc Folder > Projected Textures set to on. See if that improves the viewport rendering. Note: This will cause the viewport to do an additional redraw so you may see a viewport refresh slowdown. Quote Link to comment Share on other sites More sharing options...
stu Posted April 27, 2007 Share Posted April 27, 2007 No... No... This is just the crappy openGL... I already gave up the idea to be able to combine the two projections in Houdini... What I want to do now is render the patch separately...But it is all aroyund my geometry... I am not able render it only where it should be Yeah, I realize that what we're seeing in the image is a result of OpenGL, I was referring to your original render problem. Quote Link to comment Share on other sites More sharing options...
Symbolic Posted April 28, 2007 Author Share Posted April 28, 2007 ...hey! I have found the solution... It was me just being stupid In the Camera Projection Texture settings... It was repeat... I changed it to "Decal" and it is good now... Thanks everybody. Quote Link to comment Share on other sites More sharing options...
marin Posted May 2, 2007 Share Posted May 2, 2007 Hi, I cant get my head around camera mapping in Houdini. The Help file does not cover much on the subject. Could someone tell me how to set up a basic camera projection? I been trying to set up something similar to what Symbolic have done but I stumble at the first hurdle... regards marin Quote Link to comment Share on other sites More sharing options...
GallenWolf Posted May 2, 2007 Share Posted May 2, 2007 Hi, I cant get my head around camera mapping in Houdini. The Help file does not cover much on the subject. Could someone tell me how to set up a basic camera projection? I been trying to set up something similar to what Symbolic have done but I stumble at the first hurdle... regards marin I was playing around the camera mapping several weeks back, you can check out the sample file I posted here: http://forums.odforce.net/index.php?showtopic=5186 HTHs! Alvin 1 Quote Link to comment Share on other sites More sharing options...
marin Posted May 3, 2007 Share Posted May 3, 2007 I was playing around the camera mapping several weeks back, you can check out the sample file I posted here:http://forums.odforce.net/index.php?showtopic=5186 HTHs! Alvin Alvin, Perfect! Thanks alot Alvin. /marin Quote Link to comment Share on other sites More sharing options...
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