'Kick-ass' projection mapping technique

[John Bigboote]

http://www.cgmeetup.net/home/kick-ass-animated-3d-comic-book-sequence-breakdown/

[robcat2075]

So how do they get they artwork onto areas not visible in the original angle?

[John Bigboote]

I would suppose they could map images in at any point of the camera move, generating themselves a reference frame to conform the art to first.

[robcat2075]

There's gotta be some important step they are leaving out about how they are getting the textures for the portions of the model that were not visible in the original artwork.

[largento]

It's likely they are working with the art team to create the art they need. The art can be created in layers so that the background is whole. Additionally, I think they are probably providing different angles of character drawings to be used on the models. I don't think it's a straight conversion from a comic page. It does seem like they are holding back on showing that part of the process.

[pixelplucker]

Used that a little in my old EI days with camera projection mapping. Basically you could use different objects to catch an image projected on them, even mix it up with multiple maps and multiple projections. Creates a false depth from a flat image.

 

I think it is something they could implement in AM fairly easily.

 

Projection image can be a still or even sequence loaded like a rotoscope and the catching objects or groups would show the still or sequence. The projected image(s) are always facing the camera and only shown the tagged objects.

[robcat2075]

I'll note that projection mapping is already implemented in A:M.

 

You can indeed apply a decal through the perspective of the camera in the Chor. I forget the exact sequence of steps.

[John Bigboote]

Yes, I remember we have that cool feature. I think the steps would be:

 

-comic book artists draw main layout frame using good perspective and no 3D limitations.

-3D modelers generate geometry that matches that art, and project the art upon it, via camera mapping.

-camera is then animated to zoom thru the scene.

-at certain points it is realized that more drawn artwork is needed- rotoscope frames are generated.

-Comic book artists use rotoscopes as templates to draw more artwork into.

-new artwork is mapped via camera onto 3D geometry from same frame.

-rinse and repeat on other frames as needed.

[pixelplucker]

If I remember right there wasn't the same implementation of projection mapping where the roto would project on certain objects, think I had some problems with the way to do it in AM and gave up because the results didn't work out.

 

I'll take a look at one of my old projects I tried it with and see what the problems where.

 

Way I did that in EI is I took the projection map image and used that as a background to model against. Shapes just needed to cover the model or areas you wanted to projection map onto then I imported those objects into EI and set the projection map to just them and the same image was used as a background.

[robcat2075]

I've had trouble with A:M projection mapping in cases where very small (to the camera's eye) patches were also turned at a high angle so they were seen nearly edge-on.

[Rodney]

The tricky part of the process (the one I always have to re-remember) is to select the model's original container in the Objects listing of the Project Workspace listing just prior to applying the decal. If we don't do that we can't apply the decal. By doing that A:M thinks you are applying a regular decal... just from the current view/camera perspective.

I note that it often -looks- like the decal is applied to everything in the scene but the decal only sticks to the model you select in the PWS.

[pixelplucker]

If I remember right Rob has it dead on, patches at low angles didn't show the map.

 

In EI it didn't matter, the objects were just like a projection screen, there was no uv mapping involved.

[Rodney]

patches at low angles didn't show the map.

 

Don't forget though that after application the decal can be edited to allow those patches to properly show a more proper mapping.

 

You can indeed apply a decal through the perspective of the camera in the Chor. I forget the exact sequence of steps.

 

The primary (and crucial) step to apply the decal via the Chor view is to select the model under Object in the Project Workspace listing.

If there is another way to apply the decal via camera view I'd love to hear of it.

[Rodney]

This is just a test to recall the process of applying a decal from camera view.

Of course I'd have to wrap my head around how to optimize this for 2D line work....

Some folks doing something similar for a contest way back in the v8.5 timeframe.

Most of the imagery there was stamped/projected onto flat 'cards'.

Other things I recall from that were that there was some controversy over whether the entry qualified as '3D'.

I even remember some of the comic-related imagery that was applied to the 3D cards; Mike Grell's 'Shaman' was one of them.

 

Unrelated: I need to check to see why parts of the cube aren't reflecting on the ground... although unintended... that could prove to be useful.

I recall having a similar discussion before regarding reflections but I've long ago set aside that exploration.

I believe it had something to do with reflecting an image that was behind a camera behind the objects displayed in front of the camera.

decaledcube.mov

[pixelplucker]

Not quite, looks like the decal is stuck to the cube via camera projection.

The effect you want is the texture to remain in place so use a roto. That make sense?

[Rodney]

The effect you want is the texture to remain in place so use a roto.

 

That decal is an animated decal... so it has parts that move and parts that do not.

I was playing with that because that would be how we might animate the movement of a face... someone talking... eyes moving... all from a series of drawings rather than actual articulated models.

 

That make sense?

 

No, not quite. I'm not following what you mean by suggesting a difference between a texture remaining in place vs a decal remaining in place.

A roto won't work as well because it's stuck to a plane with no depth (unless that depth is faked by distortion, bump, etc. (which is what is animated on the cube BTW).

 

The test here was mainly to project an image onto a shape other than a flat plane and have texture stick while moving around corners of the geometry (i.e. the left side of the cube.

The next test might be to do the same thing on top of a humanoid model to 'catch' a drawing of that character.

As with methods of creating psuedo 3D movement with photographs there is a limited range of movement before the method is betrayed but using multiple instances of decals (or rotos) blended together would mask the transitions.

 

I've seen video tutorials on removing unwanted objects out of video shots using garbage mattes etc. that are somewhat apropos and a lot will depend on how much the camera moves in the scene. If the camera stays put though, that kind of defeats the purpose of the motion in the motion comics in the first place.

 

Maybe we need a target to hit such as 'can you reproduce this?'

 

Added: In order to get some parts of a scene to move and other parts to stay still we just have to layer in the effects.

[pixelplucker]

What I was referring to was the way they had one of the terminators come out of the floor and it had the checkered floor on the character as he rose out. In case of the comic that Mat showed they might have been more than just a single projection.

Objects do have to line up pretty good but not always perfect and you are pretty limited on the angles the camera can look around because the images are still just flat images.

 

The cube you showed looked like the texture was stuck to it more so than projected on, maybe it was my eyes and maybe the way the texture was moving as the cube was rotated, hard to tell.