[BUG] Texture mapping -

CoolColJ · Post by **CoolColJ** » Mon Aug 27, 2007 11:16 pm

There appears to be some some texture/UV mapping bug.

look at the attached pic.

The texture is just Colour and Bump map I created with BodyPaint within C4D.
On the left side you have the textured model as exported out from C4D with Cindigo, and exported out into Blender and used Blendigo to confirm the bug.
On the right side is the native C4D renderings etc. Anti-Aliasing has smoothed some of the detail in the top right pic though

2 main issues, the colour texture map has shifted slightly upwards, noticeable when you flip between em in a picture viewer like ACDsee.
And obviously the bump map has shifted to the right!
At first I was wondering why Indigo looked so "blurry" and lacked the bump map detail I was expecting, but after looking at things closer you can see the bump map detail has shifted a lot to the right smearing things....

Since both maps line up directly with each other image wise and use the same UV co-ordinates, I don't why this would happen, must be a bug.

model and texture maps attached in supplied zip file. Colour is jpeg and bump map is PNG, otherwise it doesn't work or crashes Indigo when I either have both Jpeg or both PNG respectively....

zsouthboy · Post by **zsouthboy** » Tue Aug 28, 2007 12:36 am

They all look exactly the same to me.

The "color" difference is because of your whitebalance & tonemapping.

The "offset bump map" difference is subtle sunlight direction changes.

CoolColJ · Post by **CoolColJ** » Tue Aug 28, 2007 12:53 am

nope I checked the bump map image there is no bump map in that smooth red area where the letter "o" is

I can do a better test by making a big obvious bump map on a check pattern I guess

CTZn · Post by **CTZn** » Tue Aug 28, 2007 4:50 am

I don't see the problem as well. Btw if the sun position is different, the bump may look shifted as highlights won't be at the same spot... Maybe an animated gif between two images would help to see...

Kram1032 · Post by **Kram1032** » Tue Aug 28, 2007 5:47 am

the lower right pic has corrected cordinates by you?
You should try to get the light to the same direction, but to me, it looks buggy, too...

make a test as simple as possible + try to find the correct light angle

CoolColJ · Post by **CoolColJ** » Tue Aug 28, 2007 12:01 pm

there is a problem have a look at the raw image maps, and where the smooth areas are vs the rough areas.

The top right is C4D with its native rendering. The bottom right is another renderer exported out from C4D, it has no problems apart from the wrong colour balance

I'll use a sky dome/background colour, problem solved for lighting

and an obvious pattern for bump map with colour on top for reference

BTW is C4D the bump map is set to 100%, what would that correspond to in Indigo? I use a bump map B value of 0.01

CoolColJ · Post by **CoolColJ** » Tue Aug 28, 2007 2:02 pm

holy crap I discovered something! The mapping is fine it's just that Indigo inverts the bump map.....

pics and scene to prove it in a sec!!!

BTW should the Bump map have an exponent of 2.2 or 1.0?

a bump map "B" value of 1.0 seems to corresponds with C4D's bump value of 100%

CTZn · Post by **CTZn** » Tue Aug 28, 2007 2:55 pm

yes bump values are linear, 1 is fine. Never used textues yet, but that may mean that exponent have an impact on bump slope.

So there is no bug !?

CoolColJ · Post by **CoolColJ** » Tue Aug 28, 2007 3:14 pm

no UV mapping bug, but there is a bump map value bug, it's inverted!

Indigo does take negative values for bump map so you can reverse it that way, but still this needs to be fixed.....

anyway I have some pics, and scene coming up to show all this along with various levels of bump and how it related to the original bump map image and C4D. Inidgo does show more bump map dynamic range than C4D, which can be good and bad. I mean in the sense even the low levels get bumped

CoolColJ · Post by **CoolColJ** » Tue Aug 28, 2007 5:48 pm

here is is - attached is the scene with a bump map "b" value of 0.001

the pic tells the story, when using a positive bump map "b" value, the bump map is inverted....
now Indigo can take negative values, so you can fix it that way, but it's still a bug IMO

interestingly a high bump map value doesn't increase the visual size of the bump, but just compresses the bump map range...not what I was expecting. As values around 0.001 to 0.003 matches the C4D bump value of 100%, but doesn't seem to stick out as much.

And the highest value of the bump map is not quite at maximum either.
But Indigo does show more of the low level detail in the bump map

I had to use a Reinhard tone mapping burn value of 4.5, pre and post scale of 1 to match the C4D image. With E colour balance

oh yeah exponent values of 2.2 don't work too well...

CTZn · Post by **CTZn** » Tue Aug 28, 2007 6:24 pm

oh yeah exponent values of 2.2 don't work too well...

2.2 is quite strong as an exponent (for bump), stick between 0.5 and 1.5. In your case the effect is even less obvious because you have a map with strong contrast, and anyway it doesn't work "better", just changes the effect in a subtle way... For instance if you want to bumpmap a slope, you will create a linear gradient from white to black and that bump mapped slope will look straight, but when you change exponent it will look incurved or bumped, got my point ?

For the issue you are reporting I can't tell much but I wouldn't be very surprised if that was related to your scene

zsouthboy · Post by **zsouthboy** » Tue Aug 28, 2007 11:58 pm

My bump maps aren't inverted in my indigo renders (exponent maps, either, for that matter).

Strange result.

CoolColJ · Post by **CoolColJ** » Wed Aug 29, 2007 9:54 am

with an exponent of 2.2, I found the white part of the bump map to be inverted, no matter wether I use a positive or negative bump map

[BUG] Texture mapping -

[BUG] Texture mapping -

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