How can I make a PP material that desaterate Green,Blue but Not red?

**Oblivion2500** · 05-23-2010, 09:08 PM

How can I make a material in Unreal Editor that desaturated only blue and green but red is still saturated. I want to make a Post Process filter that keeps only the red color but everything else is black & white? I do not have a lot of experience with the unreal editor but others showing me pictures or the .upk file, show me how you did it. I am a visual learner...

Here is a example of what I want:

**Sp4der** · 05-24-2010, 02:48 AM

why don't you use a post-processing volume?
otherwise, you could try make a red-translucent material,
so that only red light can pass through...

**Syphix** · 05-24-2010, 07:42 AM

Post processing volumes are not colour specific afaik, so the best you could do using that method would be to totally desaturate the entire level, and then highlight in red. This would not achieve what you want though.

I have been experimenting with materials and have come up with a result similar to what you want, but maybe not so pronounced. With a little more fiddling you may be able to get a better look, I don't know. Anyway this is what I did.

Connect the texture sample to two Masks, select one as (G), one as (R). Put in a Clamp and connect the (G) mask to the min value and the (R) mask to the max value. Also connect the same texture sample to the input on the clamp. This should create a filter for only Red on that texture. Just before the textures are inputted into the final material, you need to have the standard texture completely desaturated, and then use the Add function to combine the desaturated texture and the Clamped texture, which should create a black and white texture with only the red showing. The failing in this method is that it will show the reds in other colours, such as orange and lilac, they will just be a different shade of red to anything that was originally red. I am sure with more adjustments and a better clamping method these could be removed, but I haven't experimented for too long.

**Oblivion2500** · 05-24-2010, 04:09 PM

Originally Posted by Syphix

Post processing volumes are not colour specific afaik, so the best you could do using that method would be to totally desaturate the entire level, and then highlight in red. This would not achieve what you want though.

I have been experimenting with materials and have come up with a result similar to what you want, but maybe not so pronounced. With a little more fiddling you may be able to get a better look, I don't know. Anyway this is what I did.

Connect the texture sample to two Masks, select one as (G), one as (R). Put in a Clamp and connect the (G) mask to the min value and the (R) mask to the max value. Also connect the same texture sample to the input on the clamp. This should create a filter for only Red on that texture. Just before the textures are inputted into the final material, you need to have the standard texture completely desaturated, and then use the Add function to combine the desaturated texture and the Clamped texture, which should create a black and white texture with only the red showing. The failing in this method is that it will show the reds in other colours, such as orange and lilac, they will just be a different shade of red to anything that was originally red. I am sure with more adjustments and a better clamping method these could be removed, but I haven't experimented for too long.

Can you print screen and show me the picture instead please? But I will try that. P.S. I also have to make a texture sample of what?

**plugh** · 06-02-2010, 03:48 PM

Here's a simple colour pass filter, it might be what you're looking for :

This Image Was Automatically Resized by using the Screenshot Tag. Click to view the full version

**Syphix** · 06-02-2010, 08:26 PM

Originally Posted by plugh

Here's a simple colour pass filter, it might be what you're looking for :

Go with that one. The effect is a lot better than I achieved :P

**plugh** · 06-02-2010, 09:02 PM

Well it works fine with the base colours of red, green and blue. It would be nice to know how to get it working with colours such as yellow, if I get time I'll have a play.

**Oblivion2500** · 06-03-2010, 03:42 PM

Originally Posted by plugh

Well it works fine with the base colours of red, green and blue. It would be nice to know how to get it working with colours such as yellow, if I get time I'll have a play.

Do I need a texture to make the PP effect? or no?

**plugh** · 06-03-2010, 05:28 PM

I believe you need to replace the Texture Sample in the material with a Scene Texture Sample, in it's properties set ScreenAlign to true. You will also need to set up a Post Process Effect using your new material. You must then edit your UTEngine.ini, and change the DefaultPostProcess to point to your new Post Process Effect.

Here's a UDK tutorial which may help somewhat : http://www.daveprout.com/hack-this/2...cts-chain.html

**Oblivion2500** · 06-08-2010, 10:19 PM

Originally Posted by plugh

Here's a simple colour pass filter, it might be what you're looking for :

Can you give me that round rainbow texture for me to download? What is Param 'CutDesaturation' and Param 'PassColour'? Sorry I am sort of new to post process materials.

**Wormbo** · 06-09-2010, 11:26 AM

Dude, you don't want a rainbow, but the screen content. Remember, you asked for post-processing and only got an example for a static texture.

**Oblivion2500** · 06-09-2010, 11:52 AM

Originally Posted by Wormbo

Dude, you don't want a rainbow, but the screen content. Remember, you asked for post-processing and only got an example for a static texture.

Ok. So I don't need diffuse texture at all? I run into some problems if i get rid of it. What is Param 'CutDesaturation' and Param 'PassColour'?

**Wormbo** · 06-09-2010, 02:06 PM

Looks like the amount of desaturation and the color to keep. Of course you need to add a screen sample expression in place of the texture sample.

**Syphix** · 06-09-2010, 07:40 PM

Originally Posted by Oblivion2500

Ok. So I don't need diffuse texture at all? I run into some problems if i get rid of it. What is Param 'CutDesaturation' and Param 'PassColour'?

Just do everything that was done in that picture, but use whatever texture you require for the mesh in place of that rainbow texture that is being used as an example.

**Oblivion2500** · 06-09-2010, 11:04 PM

I can't find Param "CutDesaturation and Param PassColour'. Where can I find it/What is it called?

**plugh** · 06-11-2010, 01:19 AM

CutDesaturaion and PassColour are just names I gave to the parameters, CutDesaturaion is a Scalar Parameter which controls the amount of Desaturation applied to the colours which aren't your pass colour (in this case green and blue), and PassColour is a Vector Parameter which allows only one particular colour to pass through (in this case, red).