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which is a better static mesh for a floor?

im making a few pieces of floorplan that the player can assemble to their design of floorplan…
i was wondering which is better?

a plane static mesh 1x1x1… or a cube that is 1 x 1 x 0.1 ?
with sockets so they can connect with each other when being assembled…

im thinking a plane is better since its less than the cube, and i only need the top surface to be walkable…

a plane its X*X and of course its cheap than a cube

if you can use a plane use it, normally i need the sides and can remove the bottom others need the bottom.

Another problem if you remove the sides/bottom or using a plane if you spam to assemble in runtime perhaps player before assemble not see the plane (except if you activate the check box “double side”) but that depend how work what do you want.

Other problem its if you are using a irregular terrain.

like say before use it if you can, you can change that later if you found problems.

Well, in terms of polycount you are better with a regular plane (100x100x0). However this might cause all sorts of issues later on, you may get light leaks, weird calculations of distant mesh fields (if you use them), or collision errors like objects or the player falling through the surface depending on how you setup your collisions. In general it is better to use a regular box model like 100x100x25 no matter the extra tris it will have.

I would most likely do the same as ‘knack’. You could start out with a cube (100x100x100), but then remove the bottom face, as you wont need to see the floor from underneath.
The reason for this is because of Chris.R’s reason;

yep haven’t sides can cause that, and if the snapping ins’t perfect player can see through the floor in the unions. You can have few problems with planes.

That depend how you going to use the planes but when i try things like this i finally use cubes.

i see… i guess id stick to the cube and just remove the bottom… thank you for all your comments…

A box is always better, if your planning on having the plane detect hits at any point even if something hits it you’ll need a box collision (minimum) you can’t have a plane collision.

I discovered this about a week ago, its doesn’t actually say “you need a box around that plane” but I’d just thrown a auto convex and it tried to create a plane collision (or the closest it could).

In the end I’ve manage to get it to be happy with the plane (with box collision) but I do get terrible light leaks and you also can’t use overlap because the overlap needs a volume to give correct begin and end overlap outputs. I.e terrain will not give correct overlap information at all, even if you use traces (box, sphere).

hmm… just a question, how do i turn off the bottom face of a static mesh?..
go to BSP edit and delete the face? just like that?..

UE4 itself can not delete faces from meshes, you need to turn it off (delete) it during the creation process in your 3D software. It’s easy, in your 3D software (should be the same for almost all of them) just select the face you want to delete and hit Delete on your keyboard. :slight_smile:

I come from the old school train of thought where we were constantly trying to cut any polygons that weren’t visible just to squeeze things into the polygon budget. But really, ue4 can handle a lot of polygons and the 2 to 10 polygons you save by eliminating the bottom and sides really isn’t worth the problems with light leaks. plus those polygons can always just be really small in your uv map, so you really don’t even have to waste texture space.

But, we do also have the “cast shadow as two sided” flag. So if you really have to use a plane, that can help with the lighting issue. But, I suspect that could be more expensive than the extra polygons. Not sure because I haven’t tested it.

it might help for vr…