Chromakey mistakes out of your renders \(^o^)/

I just discovered my very first Blender trick to save time and fix mistakes!!!

I was rendering an animation with an environmental texture and and some aluminum material was rendering like garbage ( a massive number of fireflies ).

After an evening of brainstorming I can up with a solution to rerender ONLY what I needed.

Since there was another object between the aluminum objects and the camera and since it was animated I needed to rerender those pieces too:-?

I didn’t need or want those pieces except they blocked the aluminum and changed position because of the animation so I had no choice but to include them.

I reduced render times from almost 2 minutes a frame to less than 20 seconds at most.

I:

  1. Hid or deleted everything that I didn’t need to rerender.

  2. Changed the object/s blocking the aluminum to a 100% blue emission shader ( green works too ) at a power of one.

  3. Checked the transparent box in film under render settings to make the environmental lighting invisible in the render.

  4. Set both clamping settings to 0.5 under sampling to remove most of the fireflies. Fix whatever you need to in this step.

  5. Set the start and end frames and let it render :slight_smile:

Next I’ll:

  1. Set up the original render and fixed render in the node editor.

  2. Use a chromakey node to remove the blue objects in the fixed render.

  3. Put the chromakey output into an alpha over node on top of the original render.

Done!!

Ready to output to video or stills!!!

In my case I learned how to fix the fireflies mid render so I will need to sync the start and end frames for the alpha over with the same frame numbers in the original render.

I saved myself probably five plus hours of rerender time on a 10 to 12 hour render, it took under an hour, to rerender about 200 frames.

Anyway there it is, my very first time contributing something BACK to the Blender community.

If you have any questions I’ll try my best to answer, but please understand that I’m still very much an amateur.

Happy Blending,
Tim

P.S. This would make an AMAZING addon for mistake/ accident prone Blender’s like myself. If anyone out there wants to make one, or has already done so please send it to me. I’d thank you from the bottom of my heart.