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Electric guitar

Posted: Wed Jan 02, 2008 4:59 am
by doublez
I'm working on an electric guitar for my first big scene to render with indigo, but I'm having a hard time getting the lighting how I want and don't know what to do. Everything I do ends up looking like the attachment. I don't know what settings to change and where to put things to get lighting like this ( look at "cap") Please help, thanks.

Posted: Wed Jan 02, 2008 5:16 am
by BbB
There are a number of problems.
1) Get rid of the black void behind your guitar. If you're using Reinhardt tonemapping, Indigo will compensate for the black by overexposing everything else. So you'll keep getting these harsh, rough-edged whitish images. So put a wall behind your guitar (and not a deep black one).
2) Soft shadows = large emitter planes. Telling from the sharp shadow under your guitar, you're using one tiny emitter plane just above your scene. You don't want to do that. Instead put one large square emitter (about the height of your guitar) to the right of your scene and another one to the left, slightly behind it and slightly higher than the other. Both should have faces and normals pointing towards the guitar.
3) Coloured emitters: That's what's giving the nice warm feel in the image you mention. Give your left-hand emitter a slight blue tint (go easy, not too much, it should be pretty close to wight) and give the other an orange, reddish tint.
See if that works.

Posted: Wed Jan 02, 2008 5:23 am
by Kram1032
Image uses at least two lightsources of different angles and softness (which can be translated as size^^)
One stronger on the left and one slightly weaker on the right.
Both should be white...
Not sure, but I think, it even uses a third lightsource, even more on the left... Nearly directly from the left. It seems to be the smallest...

It's about like:

___> = medium bright light from the left (slightly from the front, but mainly left), fairly small

/ = medium bright light from the front left, a bit bigger than the previous one, but equally bright...

\ = darker light from the front right, bigger than the first two

AND one BIIIIG filllight from top, with medium dark brightness.... (I guess) - but as Indigo fully features Radiosity (or actually, as it's a side-effect of Indigo's unbiasedness), you might not need it...

Try it out, it could be absolute crap...

Posted: Wed Jan 02, 2008 5:29 am
by fishbowl
You may also want to try tweaking the HSV values of your colors with such over-saturation. I've noticed Saturation is a little sensitive for transparent materials, and Value can be so with diffuse materials.

Posted: Wed Jan 02, 2008 5:45 am
by Kram1032
never use one of these:

0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
for example, Paper isn't whiter than roughly 0.851 (if you assume Paper as diffuse, without SSS)
So, the highest value, that's reasonable, for diffuse stuff or phongs, is about
0.85 0.85 0.85
Pure black is ok, as it doesn't slow down the render, but it's fairly unrealistic. Nothing's a perfect absorber...
Try values around 0.05 as your lowest (or what does black Velvet/Silk have? That could be a nice lowest value)

Posted: Wed Jan 02, 2008 5:51 am
by ViennaLinux
Kram is right. I made a big mistake in my earlier renders. I set paper to diffuse with RGB set to 255/255/255 (so 1.1.1). Then that was a big mistake because everyone told me that the paper on the floor does not fit into the scene and all told me that I pasted it with photoshop ^^

Next time I will use a dirty greyish paper.

Posted: Wed Jan 02, 2008 6:56 am
by doublez
Thanks for all the replies! I tried what BbB said and it looks better, but I think I did it wrong and it still doesn't look great.

Here's what I did - ... tsetup.png
The 2 objects highlighted are the emit planes I made, theyre as tall as the guitar and 3 blender units wide.

Here's what I got - ... 213042.png

What could be fixed yet?

Also thanks for the advice kram, I had the pickguard at 1,1,1 so I lowered it to ,.85,.85,.85.

Posted: Wed Jan 02, 2008 9:41 am
by Kram1032
those lightsources are still too small ;)
and I'd lower the saturation of that guitar even more:

Try 0.64 0.05 0.05 :)

Posted: Wed Jan 02, 2008 10:53 am
by doublez
I made them 6 times wider (18 BU's, for scale the guitar is about 7 wide) and I got this, which looks better, but could still be better. Should I add another plane, make them even bigger, move them farther away, change the color? I also used your suggestion for the guitar color, next time I'm going to try darker, like .5,.05,.05


pic - ... 226704.png

Posted: Wed Jan 02, 2008 12:03 pm
by Kram1032
that's quite good, already :)
Try all of what you said, until you're satisfied^^ (I know, not very helpful...)

Which gamma are you using for the colour, btw? I think, it should be far darker, already... try to set gamma to 1 ;)

Posted: Wed Jan 02, 2008 12:45 pm
by doublez
Where do you set the gamma? Theres 3 of them, the one under albedo is 2.3 and the other 2 (bump and exponent) are at 1. What does gamma do?

Posted: Wed Jan 02, 2008 1:09 pm
by Kram1032
gamma controls the brightness of the image...

are you using a texture for that guitar? (I mean, for the red part)
If so, try the following:
set B to 0.64 and c to 0.05

else, there should be a gamma value, somewhere, else... where you see the material... not where you see the texture...

Posted: Wed Jan 02, 2008 1:24 pm
by doublez
The only othe gamma setting I can find is under the "system" tab? That one is at 2.2. The red part (the body) doesn't have a texture, but the neck and the head do.

[edit] I did some more testing and I think this is the best one I got ... 237716.png

I used 2 planes, both an orange, around the same placement as before, and about the same size.

Posted: Thu Jan 03, 2008 4:14 am
by Kram1032
that's very nice, now :) the red looks good!
The white might be a tiny bit oversaturated, but it's ok, anyway...

Posted: Thu Jan 03, 2008 6:45 am
by doublez
Thanks. All I have left is a few modeling things like the strings, and some cords and I have one material left; You prbably can't notice it but 2 pieces on the head are untextured. I'll try darkening the white a little more too.