[Jadrien]

Yeah I agree, like I said it's doubtful this is the best solution, this was all guesswork on my part as far as using lambert shaders are concerned. For my own projection work I just layer surface shaders. You might want to give those a try, or just project in nuke. Anyway, good luck!

[miragenz]

ha knew there'd be a catch... all very well on a black bg but you need the alpha to knock out the geo... still its works I may actually have something that moves by the end of the day :)

[Alex Jenyon]

Photoshop, despite being the industry standard in image manipulation, is often pretty rubbish at dealing with alpha channels properly.

The only foolproof way I've found (and the one we use at work) is the exact method Jadrien described - save a .tiff with 'embedded transparency'. Easy, fast, and it works.

I've had issues with surface shaders and incandescence maps in the past, so I would set up my lambert shader with 'Ambient Colour' set to 100%, and 'Diffuse' set to 0. Not entirely sure at a basic level how this is different from mapping the incandescence, but it seems to cause less issues with alpha fringing, so it's the way I've always done it.

Actually, I'd much prefer to be setting the entire thing up in Nuke, but that's not a very helpful for the discussion at hand.

Look forward to seeing the finished shot.

AJ

[nickmarshallvfx]

I normally have my shaders set up in the way Alex describes, and never had any issues like you describe here. As far as my knowledge goes, if you set your ambient to 1 then the illumination will all be what is in the image, but it won't be actually emitting light as it would with incandescence shading, causing other parts on the object to glow as you seem to describe here. My knowledge of shaders isnt extensive though, and i normally run to Nuke once my geo is all set up unless i have a specific reason to stay in Maya (such as reflections etc).

N

[miragenz]

oh that'd be right... of all the things I tried I didnt do that lol... well have done a rough and ready move... looks naff needs some atmo or something as the high res one looks like a miniature!... having probs with the ground plane lining up with the feet of the gate... maybe in the wrong place... will experiment.. is there a sim or some technique in maya that is easy to create dust? I'm tryin to do this all in maya... next one is maya/nuke... thanks for all the help so far! dave
link to a 2mb file here http://www.miragedesign.co.nz/uploads/dt_maya1.mp4

oh.. when you make a plane for a tree or the ground etc does it make any difference how many subdivisions it has and what the ration of them is?

[Alex Jenyon]

Looks like you've got some pretty heavy texture filtering going on there, even accounting for the compression. I would normally turn all filtering off (or at least way down) when doing projections, unless it's a really fine noisy image (like gravel/sand).

Maya fluids have some 'blowing dust' presets that might work. Not saying that fluids are easy (they aren't), but if you are happy tweaking a preset, and use a small container, it should get you something pretty quickly.

As you have probably spotted, camera projections are quite forgiving (unless you are doing stereo, but that's another can of worms). The ground plane can be a single polygon if you want - the subdivisions make no difference with projections that I am aware of. However, if you cut the plane twice, and then snap vertices to the bottom of the gate, you can make sure that it won't slip at all. The ground might not be perfectly flat anymore, but it's unlikely we'll be able to spot it in a shot like this.

[miragenz]

is the filtering in the lambert? I had effects off and filter none... now that I've made it move its boring... lol ..it would probably benefit from some live action.. more than just dust!... hmmm I've animated a palm in vue could drop that in... will sleep on it... couple of moves linked... would be nice to lift the camera but painting all the tops of the buildings could take a while :) dave
www.miragedesign.co.nz/uploads/dt_maya2.mp4

[Jeremy Schichtel]

Looking good. The filter option can be found within each projection texture you load:



Setting the filter to off will prevent your final image from looking too fuzzy.

I like camera move A more.

[Jeremy Schichtel]

This is the easiest way I've found to combine multiple camera projections into one shader.

1. Find the error that needs touchup.



2. Create a new camera to project the correction. Make sure to lock the camera's translate attributes when you have it where you like. Also ensure that the film aspect ratio is correct. (I rendered a 1k image so the aspect ratio is 1)

Render from the new camera and save it as a targa/tiff.



3. Paint corrections. Save out your rgb and alpha for projection in maya.





4. Set up a new lambert shader, projecting these images with the new camera, just like you have done before. (make sure ambient color is all the way to the right and diffuse is set to '0')

5. Create a Layered Shader node. With the layered shader selected open the attribute editor. Middle-mouse-drag the touch up lambert in first, then the initial shader. Delete the extra color by pressing the 'x' under it.



6. Apply this layered shader to your object.



If you had to apply another touch up to the same object, you'd repeat this process and plug it into the layered shader to the left of the previous projections.

Hope this helps the process seem less convoluted!

[miragenz]

thanks jeremy... got that working... on the layer shader menu you have a render pass mode of 'pass through' should that be for both layers or just the patch?

also in the case of my gate, on the left hand side at the beginning of the camera move the inside side wall is hidden but revealed at the end so need a texture... but because of the rough brick edge I seem to be having trouble making something fit... is the patch method best here or should it be a new piece of geometry?... must happen all the time when you go around buildings... anyone know? cheers dave