How much do blendshapes affect game performance

Questions & Answers
1

I have a character with a few hundred morphs (blendshapes). This character also has clothes that contain a similar number of morphs to ensure they fit.

If I export the .fbx model without any morphs (blendshapes) then the file size is around half a megabyte. If I include all the blendshapes the file size goes up to over 25 Megabytes.

I really like having all those blendshapes for altering my character appearance. However, I wonder how much it impacts the games performance.

Will it ‘just’ impact on the size of the final executable and not have a significant performance hit or will all that extra data just being there and being loaded for each instance of a character significantly affect the performance?

Is it worth-while going through all the morphs to work out which ones I can do without?

2

From my initial load testing, i did not notice any additional performance issues with a character consisting of 500 blendshapes. The issue is in the FBX file as you noticed where longer import times are noted. Also dont forget if you are building clothing using the blend shapes these will be significantly larger in size to.