Texture and color bug

[Micha_cg]

In the diffuse chanal is a color and texture map control. Both seems to be internal multiplied. This is good, the bug is - the color seems to be inverted befor. If I choose white, than the texture is black. If I choose red, the texture is green. I think it should work so that white (255,255,255) is the same like (100%,100%,100%). So I know it from AIR.

[Micha_cg]

Texture and color bug

... interesting, the problem is only viewable if a multiplier is used for the texture. For example if I use multiplier 2 and white color and a texture map, than I get a black material.

... if I use multiplier 1 and set a diffuse color, than the color dosn't show any effect.

I would like if the interface would show multiplier and color at the same page and the function would be:

surface color = multiplier * color * texture

[vlado]

Texture and color bug

I don't think it's a bug; the actual formula is

surface color = color * (1-multiplier) + texture * multiplier

In that case the multiplier is simply the "blend" between the color and the texture. This is how things work in 3dsmax, I suppose it is just as valid as any other formula

Best regards,
Vlado

[Micha_cg]

Texture and color bug

Hmm, "multiplier" is an confusing word here. But I understand now. One problem stay: the range of the multiplier is not limited to 0 ... 1 and the increment of the chosser is 1. I think 0.1 could be better.

Micha

[Micha_cg]

Texture and color bug

... the same problem with the reflection map. Increment 1 and no limit.

[joe_b]

Texture and color bug

multipliers are not limited to 1.

[Micha_cg]

Texture and color bug

multipliers are not limited to 1.

Yes, and this is my problem. 1 mean 100% of the image texture. More than 1 bring strange effects, if an extra color is used. Try it out.

Example: Today I have try to get a stronger reflection. So I have thought I could increase the multiplier of the reflection texture. But I have got very strange effects only. It works very confusing.

If you would limit the "multiplier" to 1 it would dosn't show strange effects. Look at your formula. Take a multiplier of 2. Than you get an inverted color + a strong texture intensity. I don't understand the decision for a "+". I would multiply anything. But if you limit the multiplier, than the user can not increase the intensity. Oh, is it difficult.

What do I need? For example I have a wood texture. In a test rendering I see, the wood is a little bit to dark. In renderman in would change the multiplier from 0.8 to 1 and would get a brighter wood texture. Than I see, the wood looks to blueish. So I would set the color from white to a little bit orange. Ready.
In Vray it is difficult. First I must know this formular. If I need a brighter texture, I must set the color befor to black (default is white). But what is, if I like to get a color shift of the texture. The color is inverted per formular. So if I want to get a orange shift to my texture, I must set a blueish value.

In renderman (AIR) I know anything is multiplied and white means 100% = factor 1. That is all. If I use a black color, than my material is black. If I use a tint, than my texture is tinted. If I use the multiplier, than the material is brighter.
Vray is not idiot proof (it's my free translation for a german (friendly) word). You can be easy confused, like in my examples. I know it know I will do it in the future. But I feel, it is not user friendly.

The problem seems to be, this system is used since a long time at 3DSMax, and so I have no chance to discuss it or?
I'm curious to know, what the advantages of the blend formula are. It seem to be, the user can wash out the texture with a tint.

Micha

[flipside]

Texture and color bug

Does renderman work with GI too? Because when you would set a texture multiplier to higher than 1, I think it will start to emit light, no?

In vray for max, you cannot set reflection strenth higher than white. If you want stronger reflections, you should increase the reflection IOR for you fresnell effect.

A texture in reflection slot is used to control reflection strength over a surface. For example on a tile texture, you would set the grooves to black, and the tiles itsself to light grey. So the tiles will be reflective and the grooves not.

I don't think changing the colors in a texture map by blending it with the diffuse color underneath it is such a good idea. After all, you will loose contrast in your map too. The ideal solution for this is a special map type, like in max, the color correct map. It is a map you put in your texture slot, and in this map you specify a texture. Then the color correct map has settings to change hue, contrast, intensity, etc...

[Micha_cg]

Texture and color bug

I have used the renderman compatible engine AIR. This support simple GI (not matured). I'm not sure what will happen in GI mode with a diffuse more than 1, but it works in non-GI-mode good. Also you could think on values under 1. Anything is relativ.
Also if you say, a value greater than one is not good, than the multiplier chooser could be limited to 1. My problem, in Vray I can not use a multiplier, because here is only a blend parameter. OK, if I set the color black, than I get a multiplier. I think, here could be the usage more userfriendly or usersafe.

I know the usage of the reflection map. I was testing, how could I get stronger reflection. The color is limited to (255,255,255) and so I have thought, I could use a texture and the multiplier. And than I have got strange effects.

>"I don't think changing the colors in a texture map by blending it with the diffuse color underneath it is such a good idea"

I'm the same opinion. I would like to get a intensity (multiplier) button instead - for finetuning a texture brightness.
For example I have used a black stone ground, but my chief says, it must be a little bit brighter. Opening photoshop is not a good workflow. In AIR I could change the multiplier only. But what can I do in Vray?
And if the chief say, she like to see a little bit brownish look, I would wish to use the color as multiplier.

What do you think about a straight multiplication for all factors?