Hello, I’m working on an interface for a touchscreen and would like to render out just the lighting in a specific region of a button element. I’d like to animate the brightness and render only the lighting so that I may ultimately display the lighting on the button only when the button is activated in my automation software. So basically a GIF on top of the static image that has all the buttons off.
Here you can see on the left the button with the lighting and on the right without. The lighting is area lights created from a ring of faces at the base of the circular button. Area lights seem to produce a better result than an emission material.
I know I can use the render region to get the square area of the button, but ideally would like to make the region pixel accurate if possible while maintaining the original background size so when I drop the small lighting gif it matches the unlit background. I’ve seen this addon for doing what i’d like, but haven’t confirmed it’ll work in 2.93/3 yet. https://blendermarket.com/products/brendon
So my main hurdle seems to be getting just the light to render with an alpha. I’m not sure how to best utilize compositing/render passes to do this. Each button is in a different part of the screen where the background is different. I don’t mind that the lighting is the same and am hoping since there will be an alpha it’ll look slightly different over the background in different areas.
Hopefully my intent isn’t too confusing.
Thanks for any replies