Help me understand smoothing groups...

Hey guys,

How essential is a smoothing group? When would I use one? Only if I am importing a bump map, or in all cases?

I’m totally confused about how to use them. Are there any good tutorials for moving from MODO to UE4?

EDIT: Also, when designing specifically for VR, does smoothing completely lose its efficacy?

It depends on what program you’re using–Smoothing groups are actually just a 3ds Max thing, a number assigned to a set of polygons that determines which polygons are smoothed together. Like on a cylinder, the sides would be smoothing group 1 and the top and bottom would be smoothing group 2.
Other programs use their own form of smoothing that aren’t called smoothing groups, and all programs have some kind of system for that.

Smoothing settings are important because at the very least it’s a way to make curved surfaces look smooth and rounded where otherwise you would see the polygons like facets on a jewel. What’s important is that it changes the normals of the object, normals are the direction that a surface is facing, so for things like normal maps it needs to make sure that the smoothing/normals are correct or the normal map won’t look correct.
And you need correct smoothing no matter what you’re doing.

I agree with darthviper, additionally it helps to understand the impact smoothing groups/smoothing splits/hard edges (whatever your 3d app calls them) as well as UV edges have on the final game model, as it can significantly increase the efficiency of your meshes if you understand how to work with them appropriately, regardless of what 3d package you use. I have found Alec Moody’s excellent explanation the most clear way to demonstrate this: