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Reload this Page camera projection
Work in Progress WIP to Critique

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(#11)
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Jeremy Schichtel is Offline
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Default 02-15-2012, 10:38 PM

You're right. You don't need to save it with an alpha. You do need a separate black and white projection that you'll plug into your lambert's transparency (black being transparent and white opaque)
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Default 02-16-2012, 04:09 AM

Its been a while since I've done a projection in Maya outside of work (where we use proprietary tools in Maya), but I think you should be able to adjust your geo providing you haven't baked the projection. Should be quick to test, give it a go and see how you get on.


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Default 02-16-2012, 06:31 PM

Hi Dave, I remember watching this challenge and liking your entry, I'm excited to see the final result! I did a quick test with a lambert shader and Nick's right, you can move/scale/rotate your geo all you want without the image stretching. So if you have to tweak the geometry into place you shouldn't have to worry about re-projecting.
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Default 02-16-2012, 07:18 PM

cool thanks, any idea why my projected images would be dark? am just using default light... I'm pretty sure I've covered off the zillion steps to loading a texture correctly :) cheers dave
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Default 02-16-2012, 09:06 PM

Ahh that's annoying. I'd double-check to make sure "Enable Default Light" is off in your render options. If that's not the problem, I'd go into the hypershade and make sure the incandescence from your lambert shader is linked to your projected image.
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Default 02-16-2012, 10:01 PM

hmmm interesting you should say that, I originally used that method but the incandescent was lighting up all the geo (even outside the alpha) with default off, a method I have heard worked in earlier versions, but it doesnt seem to work now... so was trying with default on and no incandescent... in maya 2011
if you/anyone wants to look at my file its here:
www.miragedesign.co.nz/uploads/morocco2.zip
have dumbed it down, only has the two textures plus imageplane... nothing lines up at the mo but if you take building 6 geo and plug in the two textures it should misbehave for you... they are only 8bit to keep small so the whole file is about 6mb
cheers! dave
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Default 02-17-2012, 03:57 PM

I poked around in the file and found a couple of things to think about. The good news is I corrected the projection and got it working fine on that one building. Personally, I use a single surface shader for the initial projection on an object (and then a layered shader to arrange any secondary projections) so I've never used this setup, but it works fine with the lambert shader. Also, I'm using maya 2011 as well.

As I understand it, "lambert_build6" contains both the color and transparency projections. The incandescence wasn't linked to geo, which is why the buildings were so dark. There should be no lights in the scene since you established light in the dmp, so by setting the incandescence, you're able to control the shader's self-illuminating color, which in this case stems from your b6.tif. I linked the incandescence in the same way you linked the lambert's color, to the b6.tif. When I rendered the image it worked fine for the most part, but the projection had some ghosting.

The reason for this ghosting was because the "Device aspect ratio" in the render settings wasn't matching the "Film Aspect Ratio" from your projection camera, so the projection was failing to line up. "camera_proj" had a FAR of 1.5, when it should have been the aspect ratio of the tiffs, 2.796. To fix this just select "camera_proj" and matched the ratios. As a result, I had to reposition the geometry--they're just cubes, thankfully.

When I rendered the scene again building 6 caught the projection and the ghosting was gone. The problem was that the rest of the cube left uncovered by the projection was white. This is because when you saved out the b6.tif, there was a pink background. Make sure to save out the tifs with either transparency or a white background. When I saved out the tiff with transparency, the geometry that wasn't catching the projection was no longer visible. I assume this is the reason the "incandescent was lighting up all the geo outside the alpha".

Once I tweaked these things the projection worked just fine.

I'd suggest first matching the aspect ratios and roughly realigning the geometry. I'd then create a new lambert, if that's your shader of choice, and create the "color" as a projection with the b6.tif, create the "transparency" of the material as a projection with the b6_1.tif, and create the "incandescence" as a projection with the b6.tif.

Hope this helps, it's a bit confusing trying to talk maya without being able to point at a screen. Let me know if anything I said isn't making sense or needs further description.
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Default saga continues - 02-18-2012, 12:01 AM

hi, oops on the aspect ratio...
really appreciate your help... have pretty much tried everything I can think of and your suggestions of course, even maya 2012... have made a very simple file with two tiffs... both have alphas (reversed) proj with a lambert... if you can remove the lit geo and explain why I'd be eternally greatfull... link here...
www.miragedesign.co.nz/uploads/dave.zip (small file only a meg or so) cheers dave
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Default 02-18-2012, 08:55 AM

I'm unsure if this is the "correct" solution, but it worked for me in Maya 2011. I believe the problem lies in how you're saving out the image files. Make sure when you're saving the tiffs you save them on a transparent background (I did a crude cut out, but it's just an example lol) and with transparency checked in the tiff save options (at least for the image, not the alpha). When I reloaded the images in Maya, the projection worked fine.



I believe what's happening is that the incandescence is reading the white in the background of the image (not the alpha) as a value, hence making the cube glow. Honestly, I'm not all too sure if thats it, but it's my best guess at the moment. I'm going to look into this further, since it's raising a few questions for me as well and my knowledge of shaders could use some drastic improvement. Hopefully this solution works, let me know if it doesn't.
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Default 02-18-2012, 11:22 AM

thanks for that.. it works but I suspect its not right? you can actually save the tiff with no alpha channel, but with the transparency (as you show), then load a lambert and plug it in to incandescent, default light off and thats it! working.. no other tiffs needed for alpha and colour and no alpha channels... same with the surface shader; just the colour loaded - seems too easy :) hmmm somethings going to fall off surely... I'll go re-create all my layers and set it up cheers dave
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