davescmCorrect answer
Community Expert
August 5, 2022
Hi
What you have to do is change the four inputs to three and replace the fourth (alpha) with a constant value set to 1
Follow these steps:
1. Expose the uniform color node parameters as normal
2. Go to the graph input parameters and change Type/Editor from Float 4 to Float 3. Also change the input box next to it from slider to Color(RGB)
3. Go back to the uniform Color node and edit the function graph
4. Replace the single Get Float4 node with the function nodes below. This sets alpha to 1. Don't forget to right click and set the Vector Float 4 as the output node.

That's it.
Dave
