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View Full Version : Cam projection | per pixel map | masks ?? how why and where?


everlite
09-05-2006, 02:13 AM
Hey guys,

I've just posted quite a lengthy tutorial on camera mapping, hopefully it makes a little sense, (check the house link in my signiture) but one thing that still confuses me is how you uses masks in the camera per pixal map, i kind of understand but don't at the same time.

As an example, say i was animating a camera projection that revealed a new wall or something, would i use the mask to create the wall? ... im confused again.http://forums.cgsociety.org/images/icons/icon11.gif

Any explainations VERY weclome http://forums.cgsociety.org/images/icons/icon7.gif


Cheers - Dave.

Kutkin
09-05-2006, 03:24 PM
I'm not sure, it's what you need, but here's something:
http://mattepainting.org/forum/viewtopic.php?t=109

Nodal point tilt and pan - tutorial on digital artforum (http://www.digitalartform.com/nodalPointPan.htm)

Nodal point pan 1 (http://www.digitalartform.com/archives/2004/10/nodal_point_pan_1.html)
Nodal point pan 2 (http://www.digitalartform.com/archives/2004/10/nodal_point_pan.html)
Nodal point pan 3 (http://www.digitalartform.com/archives/2004/11/nodal_point_pan_2.html)

In this technique you use image with multiple perspectives, so no wall (or something) is revealed during the camera pan.

everlite
09-05-2006, 07:10 PM
No not quite what i was thinking about, cheers anyway.

everlite
09-05-2006, 08:44 PM
Another question that i need a little direction with,

Say i'm building a semi-panoramic scene how would i render this out? maybe the above might be of use afterall :-)

everlite
09-05-2006, 09:02 PM
Well i think i've solved the panoramic problem, i used a piece of software that stitches images together to create panoramas, so now i have flat panoramic shot, so next question is how do i corectly apply this as a projected map?

Kutkin
09-06-2006, 01:59 PM
Well, if you got one image from two, then it can't be mapped by single camera. Something like Cylindrical Mapping might work.
Or use two cameras with two images. It then creates a kind of panorama in 3D.

everlite
09-06-2006, 08:24 PM
I think this would be done with two cameras but i can't quite make the link to how this might be done, any ideas?

everlite
09-06-2006, 09:03 PM
check this out:

http://www.digitalartform.com/archives/2004/11/camera_projecti_1.html

So how does he project the other side of the box and how would this be done in max? would you use 2 cameras, map one angle then go to the other end of the animation map it from that point of view? so how does it transeed between the two?

So ut seems you use the masks to blend between the two, but how?

jussing
09-07-2006, 12:47 PM
Well, from what I can tell he doesn't project the other side of the box, he just projects it from this angle:

http://www.digitalartform.com/archives/images/forBox.jpg

Which fully projects the newspaper, and three sides of the boxes. This projection is enough to make a camera move like this:

http://www.digitalartform.com/archives/images/camProjSwoop.gif

- and not worry about the back side of the box at all. If you'd want the camera to go all the way around, you'd need another camera.

Cheers,
- Jonas

jussing
09-07-2006, 12:52 PM
Keep in mind that the camera projecting the texture doesn't need to have anything to do with the camera that renders the scene. Think of the camera projection as a DIAS projector, projection an image onto a miniature model, while moving camera films it. You can then use multiple projectors to cover all sides of the model.

Each PROJECTING camera image can then have a masks that prevents it from overlapping another camera's projection. I also believe the camera map modifiers have an option to NOT map on backfacing polys, you'll need to use that option too.

- Jonas

everlite
09-07-2006, 09:10 PM
Hey cheers, so would you use the mask to show only the areas you wish project? this kinda makes sense.

By the way, really loved your renders, the lava and pyramid.

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