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View Full Version : image projection through camera



erikals
02-14-2009, 07:53 AM
ok, projecting an image through the camera,..
why would we want this?

well,, several reasons... here's one,

retouching a video
it's common to retouch video after finished render, for example by adding highlights to the objects.
this can be, and often is, done in post, like e.g. after effects.

however, when the camera is panoraming through the 3d scene, this becomes tricky/ impossible.

in Maya, the trick around this is to camera project an image onto the scene, for then to bake all the objects.
then, with a little retouching to e.g. the highlights, the camera can pan freely, ready for the finished render.

an example where simillar stuff was done was in this scene, (note the added highlights on several objects)
made by Rune Spaans (superrune) copyright tv2

http://www.superrune.com/gallery_3d/images/2005_tv2jul_maane_back.jpg

3dworks
02-14-2009, 10:32 AM
isn't front projection doing this?

cheers

markus

erikals
02-14-2009, 09:31 PM
sort of, but i'm talking about front projection through the camera, that projects an image on to all objects/surfaces in the scene at once.

as far as i know that is not possible (?)

3dworks
02-15-2009, 11:43 AM
sort of, but i'm talking about front projection through the camera, that projects an image on to all objects/surfaces in the scene at once.

as far as i know that is not possible (?)

correct me if i'm wrong, but imo this is possible if you assign/copy the same surface containing the projected texture to all objects in the scene (best with surface editor in scene mode).

what you have to do is to assign the camera you want for front projection first ('reference camera' in the lower part of texture editor). if you need to move that same camera, clone it and animate that clone. btw. as you probably know, camera projection works only within certain rather small movement limits - means if you are moving too far off the projection axis, the effect will reveal.

if you need to superimpose that texture to the objects surfaces while they maintain their own individual surfacing, you have to add the projected texture as a surface layer in the channels of your choice. the blending mode will decide how this texture will be processed. but probably in this case there is also a more elegant node based solution, i didn't test this yet.

cheers

markus

erikals
02-16-2009, 04:21 AM
looks like you are right :)
didn't know this.

the superimpose job looks somewhat tricky, but in this case it is basically just to rename all the surfaces, project, then render. then mix the two renderes in post.

it'd be nice to be able to overide this though.
like now, i can use the spotlight with an attached texture, however i cannot make it match the camera, neither blend correct.

regarding renaming surfaces, do you know if that must be done through modeler if one's gonna rename several surfaces at once? (...couldn't find a fast way in Layout)

big thanks, didn't know this was possible, :)

3dworks
02-16-2009, 04:30 AM
looks like you are right :)
didn't know this.

the superimpose job looks somewhat tricky, but in this case it is basically just to rename all the surfaces, project, then render. then mix the two renderes in post.

it'd be nice to be able to overide this though.
like now, i can use the spotlight with an attached texture, however i cannot make it match the camera, neither blend correct.

regarding renaming surfaces, do you know if that must be done through modeler if one's gonna rename several surfaces at once? (...couldn't find a fast way in Layout)

big thanks, didn't know this was possible, :)

glad that i could help...

as for the renaming part of the job, apart doing this manually, i've found a plugin here

http://blogs.yahoo.co.jp/max3dc/28160669.html

which should do the job even for complex scenes pretty well. i've not had a chance to try this out, yet. just use google translate if you aren't practical with japanese ;)

cheers

markus

edit: DL link is broken, but you can download it here: http://www.newtek.com/forums/showpost.php?p=690984&postcount=2

erikals
02-16-2009, 04:55 AM
Great!! thanks :)