Author Topic: Editing Exposed Parameters  (Read 151 times)


I am trying to use exposed parameters in Blender. I exposed for now color parameters. I can see them in Blender, they are there but do not do anything. I went through other artists materials where their exposed parameters works ok in Blender.

I have noticed a small difference in my exposed parameters and the other artist's, what I think cause a problems on my side but I don't know how to address this and what to ask for in Google. When I edit exposed parameter which is behaving correctly after export to sbsar and import to Blender, I can see small node tree as below on first image. When do edit my parameters most of them have just one node in it as per second image.
 Anyone knows why I am having this issue?
Last Edit: July 27, 2020, 02:58:25 pm

Hi !

First, exposing the color of a uniform color by simply use the expose option should work.
What you see in other artist's graph is not very different from what you have, the difference is in how the alpha channel is controled.
As you probably noticed, in a uniform color node you can control 4 values : Red, Green, Blue and Alpha (RGBA).

When you expose the color, then double click on the background of the graph to go into its properties, the input parameter created is a float 4 to control 4 components : Red, Green, Blue and Alpha.

Most of the time, you don't want to allow changes on the alpha value because it can break your material. The solution is to change the default float 4 for a float 3. This way, users only access to Red, Green and Blue and the alpha has a constant default value set in the function.
I made a gif to show you how to do this. 
- You first start by exposing your color as usual
- then you go into graph properties and modify the type of the parameter for a float 3 instead a float 4
- then you change the type of widget for color (RGB) in order to see Red, Green, Blue sliders (but no Alpha anymore)
- at this stage, you can modify the value but your node in your graph will remains black because you control Red, Green and Blue but the alpha has no value anymore. You have to rebuilt a float 4 !

- go into the function of the output color, create a get float 3 in order to get the parameter you just modified
- create a float (it will represents your alpha) and set it to 1 (or any other value you want of course, it depends on your need)
- create a vector float 4 (it will represent R,G,B,A), right click on it and choose "set as output node" (this how you tell Designer : use this node as the result of the function)
- plug your get float 3 in the first input (which represents R,G & B)
- plug the float node into the second output
Here it is ! you just rebuilt the float 4 using a float 3 !

But as I said at the begining, it shouldn't change anything in Blender. So you can try what I explained above but feel free to send me your project if you still have the same problem. I can make some tests on my side ! :) 

QA Analyst