Your thoughts on the current TexMap and Color Mults( Blend)

[joe_b]

As some of you may or may not have seen, Micha has brought some things to my attention about how our texture maps and colors are a bit confusing having multiple multipliers, and that the "multiplier" for the texture maps is really a blend factor. I don't want to plead Micha's case for him, so you can find the topic here and read for yourself http://www.asgvis.com/phpBB2/viewtopic.php?t=372 (About half-way down the page)

So basically, before I take any further action on this I would like to know what other people think about the current methodology.

[Thomas An._cg]

Your thoughts on the current TexMap and Color Mults( Blend)

I don't see a problem with the color having its own multiplier and the texture having its own too.

We can set either one of the multipliers to zero (0) in order to disable. If both are 1.0 then they contribute equally (blend)

[Micha_cg]

Your thoughts on the current TexMap and Color Mults( Blend)

I would like to get one multiplier and that the texture and the color are multiplied:

multiplier * color * texture

advantages: full color and brightness control of textures

[Thomas An._cg]

Your thoughts on the current TexMap and Color Mults( Blend)

I would like to get one multiplier and that the texture and the color are multiplied:

multiplier * color * texture

advantages: full color and brightness control of textures

I find that confusing.
Having two multipliers seems more straight forward and you also control brightness and color. Having a single multiplier also seems less flexible, because you can't control the influence of either the texture or the color separately.

You can have the same effect as you describe by setting both multipliers to the same number.

[Micha_cg]

Your thoughts on the current TexMap and Color Mults( Blend)

I would like to get one multiplier and that the texture and the color are multiplied:

multiplier * color * texture

advantages: full color and brightness control of textures

Thats confusing

multilpier -> brightness of the texture or the color

color -> color adjustment of the texture or without texture only pure color

In renderman a white color is the same like a multiplier (1,1,1) or (100%,100%,100%). If you multiply a texture with a color, than each pixel is multiplied per color. If we don't get acess to multiplier values above 1, than we could cut down the multiplier, the color and the texture are enough, because the color is a RGB multiplier. What do we need more?

[Thomas An._cg]

Your thoughts on the current TexMap and Color Mults( Blend)

If that is the case then Renderman does not have a good UI and it should not be implemented. It is too abstruct and cryptic. The user doesn't know what is happening behind the scenes unless you tell them the formullas (Mult*Color*Text) and even then its confusing.

You can still do what you say by having two multipliers and set them to the same value. (or just leave the texture multiplier to 1.0 and play with the color multiplier only. It is the same thing.)

Think of it this way:
You have two layers in Photoshop and the blend mode="Multiply". One layer is a single color and the other layer is a picture. Each layer in photoshop has its own transparency slider. So we are transfering this interface to Vray...


In ergonomics, less buttons is not always better. As a matter of fact some of the worse interfaces have too few buttons.

[Micha_cg]

Your thoughts on the current TexMap and Color Mults( Blend)

I don't understand for what I should need a blend function? I could wash out a texture with a color. Do you need it? Most I need a color adjustment of a texture and a brightness control. But I have the feeling, with the double multiply control you can not easy adjust the color of a texture. Could you write a formula so I better understand?

[flipside]

Your thoughts on the current TexMap and Color Mults( Blend)

I don't understand anything of it. If I have a hdri als BG for reflections, and I want it to be twice as strong, I would set the multiplier to 2.

All this stuff becomes obsolete when there is a real material editor, becuse there you could load maps too, and control the map in there and assign it to any material or BG slot.

If I set a hdri multiplier to 2, is that the same as if I would adjust the exposure in hdr shop to twice as bright? I don't want any multiplier or color blend in vray to mess up my hdri to a not correctly adjusted one, resulting in an LDR for example.

[Thomas An._cg]

Your thoughts on the current TexMap and Color Mults( Blend)

For example if I use a HDRI and I have the feeling it is too blueish for my scene, than I would like to multiply a yellowish color.

Why is your HDRI too bluish in the first place ? This is to be adjusted in post.

About formulas, I suppose it would be additive

FinalColor = (Color*ColorMult) + (Texture*TextureMult)

if either of the multipliers are zero then that part of the equation drops off. Otherwise it is color additive. (Like shining a blue light on a textured wall).

[Micha_cg]

Your thoughts on the current TexMap and Color Mults( Blend)

I don't understand anything of it. If I have a hdri als BG for reflections, and I want it to be twice as strong, I would set the multiplier to 2.

All this stuff becomes obsolete when there is a real material editor, becuse there you could load maps too, and control the map in there and assign it to any material or BG slot.

If I set a hdri multiplier to 2, is that the same as if I would adjust the exposure in hdr shop to twice as bright? I don't want any multiplier or color blend in vray to mess up my hdri to a not correctly adjusted one, resulting in an LDR for example.

LDR? A color correction does the same like the scale in HDRShop- you get a HDRI allways. The advantage, if you like a cool look, you could multiply a light blue. If you like to render a warm image, you can use a orange color multiplier. The color multiplier makes possible to render images with different look. For example you render an exterior shot - so you can use a outdoor HDRI. But if you like to render a interior shot with the same HDRI outside the windows, than you could give the HDRI a blueish look like it is if you make a photo in a room with artificial light color correction.

[Micha_cg]

Your thoughts on the current TexMap and Color Mults( Blend)

For example if I use a HDRI and I have the feeling it is too blueish for my scene, than I would like to multiply a yellowish color.

Why is your HDRI too bluish in the first place ? This is to be adjusted in post.

This dosn't work allways. For example I'm working on an architecture rendering with windows. Only I need a bluish outside and not inside the window. I don't understand what the problem is with the simple multiply function. It give us all freedom for rendering. But why should we use a blend? This question is open. And if somebody find a reason, how often we would need this blend?

About formulas, I suppose it would be additive

FinalColor = (Color*ColorMult) + (Texture*TextureMult)

if either of the multipliers are zero then that part of the equation drops off. Otherwise it is color additive. (Like shining a blue light on a textured wall).

My question stay: for what is this washout color blend function useful?

I think an addition is not so useful in image manipulation. If you add a color, you change the brightness. You can not simple shift the color impression of a texture, - you get an offset. In the worst case you explode the color range of 255. If you want to limit it to 255, how would you do it? For example color (150,150,150) + (150,150,150) = (300,300,300).

And you change the contrast. For example: the original image has a range from 10 ... 100 (1:10). If you add 100, than you get 110 ... 200 (~1:2). This is it what I mean with "wash out".

My multiply idea is not realy my idea, it come from the renderman standard. An old powerful standard. Why not use it here too?

[Thomas An._cg]

Your thoughts on the current TexMap and Color Mults( Blend)

If you want to limit it to 255, how would you do it? For example color (150,150,150) + (150,150,150) = (300,300,300).

oh, and with the multiplying idea what does 2*(220,220,220)*(200.200,200) mean ? what is that ? (88000,88000,88000) ?

I think what they do is normalize the result (either in LDR or HDR range) so effectively the two multipliers would act as a ratio adjustment (of color versus texture)

Basically I don't agree with you. A single multiplier convolutes the issue. I personally wouldn't know how to use it (but I can't speak for everyone). It is more intuitive for the interface to act like in nature where colors behave additively.

Renderman is not the best interface, there is a reason why many people avoid it. A user should not have to go through these geeky details in their head. Vray is already complicated as it is.

Only I need a bluish outside and not inside the window.

I have no idea what that means (or how it relates to the multipliers).

But why should we use a blend? This question is open. And if somebody find a reason

If we glow a yellow (or green) light on a wall painting then (by color addition) we know what we get, but color*texture makes little sense, what is the physical equivalent of that ? what does blue*Red mean ?

[Micha_cg]

Your thoughts on the current TexMap and Color Mults( Blend)

The multiplication of color and texture and intensity works with normalized values. A color of (255,255,255) is internal (1,1,1) and means (100%,100%100%). If the intesity of textures is limited to 1 (100%), than you stay in the color range allways.

Renderman is not an interface, it is an old render standard. Every year it is discussed again at the siggraph. The big book "Advanced Renderman" is a collection of lecture. Very interesting.
Every programmer can write an own interface.

A single multiplier could named "brightness" or "intensity". I think, this good to understand name.

Color addition - if I look at my photoshop layer function than I see at first a "multiply" and no "addition".
I wonder me, I give you an example of the usage: intensity, color and color correction and ask you for the usage of the blend function. But you give me not an example of the blend usage. For what do you want to use the blend "wash out" function?

If I say, I would shift the color of a HDRI, than I mean, that nobody can say, a full white balanced HDRI is useful for every case. If you render an interior scene and you want to simulate the "blue hour" outside the windows, you could shift the HDRI to a blueish look. If you would render the image with the neutral HDRI and would shift the color in post, than the interior lighting is shifted too.
Here a small example - outside blue, inside orange.


Blue*Red (0,0,1)*(1,0,0)= (0,0,0)
Multiplication works like a standard color filter. Easy to understand or?

I like the usage of Rhinoman. In the color field are viewable the normalized values, for example (0.8,0.9,1). If I click on the color field the Rhino color chooser open and I can choose a color. If I need a color shift, for example less blue, than I type in the numerical field (1,1,0.9). It is like the color scale of HDRshop and means 90% blue please. The user can choose between the numerical correction or the color chooser. The user can copy the numerical value from one material to the other.

Conclusion - for a good workflow I suggest following color controls:

• - texture
  - color (= color correction of the texture if a texture is choosed)
  - intensity
  - gamma

If the color is shown as color field and normalized value the usage as multiplier could be better to understand.

[flipside]

Your thoughts on the current TexMap and Color Mults( Blend)

I like your conclusion micha. So color will be a color box and intensity and gamma a number.

[flipside]

Your thoughts on the current TexMap and Color Mults( Blend)

Seems like this poll isn't very popular. 3 people respond, and only two of them understand the theory (I don't). So either people don't care, or they don't have a clue what's going on.

The goal imo is to have some texture correction controls. And then micha's last sum up is good. All the main corrections needed for a texture are there: color, intensity (range from 0 to infinity), gamma.

I don't really care about the theory behind it, as long as it is there it would be very nice, and if it is implemented in a logical way. So simply one row for each texture showing above controls is good imo.

The environment options are a special case, but with the above tools you could indeed leave the two multipliers and make it only one.
Texture path x color x intensity x gamma

If texture path is empty, you're using a pure color for environment. If color is white and you specified a texture, the texture is not altered because muliplying with white does nothing.

I don't have a clue how they work now. If you choose a texture, is the color field disabled? Has the color multiplier an effect on the texture?

The best thing would be a real mat editor that could load maps too. Then you don't need all this intensity and gamma control etc in the interface, but in the options of the map in the mat editor. I just hope Mcneel don't want to reinvent the wheel with there mat editor, just copy it from max, that works great.