Which is better for performance: lots of parts with more collision detail or unions with less collision?

[Va1t_Dev (Valt)]

I’ll put a huge amout of fence segments that contains 3 parts for each, and I’m not sure about should I unite the each segment into a single part with CollisionFidelity as “box” or keep the each segment as a group of 3 parts? I’m asking this because the collisions in the fence’s holes are not really necessary, and to reduce the amount of detail in collisions and improve the performance, I’m considering to unite the parts of the segment together and set the CollisionFidelity of the union to “box”.

The thing is, I’ve also heard that a large amount of unions can also cause lag, which is why I can’t decide which way I should go with.

(the selected parts are the “segment” I’m talking about)

The triangle count is 44 for each segment when I unite them.

What do you think?

[iGottic]

Try giving this a read:

Unions have awful performance // Pure DATA to demonstrate the not-so-greatness of CSG

This post is being made because I keep seeing developers make the assumption that just because Unions decrease instance count, that their performance is improved. Unions do not improve performance, and in fact, hurt performance. Only rare edge cases have been acceptable: If you need to have destruction that is extremely accurate, CSG may be required. If it does not need to be accurate, use Blender destruction simulation for best results. If you absolutely require perfectly sharp edges without…

In short, don’t use Unions. Meshes and parts are your friends.