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Re: Tutorial bump map?

Posted: Thu Jan 07, 2010 2:43 am
by madcoo
StompinTom wrote:
madcoo wrote: It has displacement of 0.01, which should be 10cm...
Nope. That should be 1 cm.

0.01 x 100 cm = 1 cm.
StompinTom, I think I need to go back to school !!!
(now I really feel dumb)

Re: Tutorial bump map?

Posted: Tue Jan 12, 2010 10:06 am
by Soup
Just to clarify, here's something I wrote for the manual (might have to simplify it, not everyone knows calculus :P)
To be honest, "A,B,C" should not be used in the exporters, I think we will try and remove that lingo and go just with Quadratic, Scale, and Offset.

A,B,C Values
The A, B, C values are modifiers for the texture map. This is the equation used (for those that have studied calculus this equation will be familiar):
x = ax^2 + bx + c

The A, B, C, values are taken from here. Thus:

A value – Quadratic

You will not often need to use this, usually it easier to get expected results by modifying the texture map with an image editing program.
Scales values by a quadratic, so low values stay low, and larger values become massive!

B value - scale/multiplier

Scales the texture map values. Can be associated with contrast. Maps the value range of 0-255 to 0-1 (for a usual LDR texture), which is then multiplied by this number. For example: a B value of 2 makes a pure red RGB 255,0,0 to 510,0,0.

C value - Offset

Total RGB offset, generally making the texture brighter or darker.

Exponent: Used for converting texture RGB values to display values (gamma). A typical value is thus 2.2. Here is how it fits into the equation:
f(x) = a*g(x)^2 + b*g(x) + c
g(x) = exponent

Tutorial bump map

Posted: Sat Mar 27, 2010 10:10 am
by Dordixs

I figured out how to use the bump material to get the details I was looking for, all I was missing was the displacement tips.

Good job, and thanks for sharing. Im itching to get to use Z2 this weekend. I wish I didnt have to work LOL

Re: Tutorial bump map?

Posted: Sun Mar 28, 2010 2:13 pm
by Headroom
Good explanation. I always wondered how the exponent fits into the calculation.

A few more real-live texture examples would be nice. No simplifications please.

Re: Tutorial bump map?

Posted: Tue Mar 30, 2010 7:22 am
by PowStudios
Headroom wrote:A few more real-live texture examples would be nice. No simplifications please.
'+1' - More examples with pictures would be great. The explanation above is valid?