Modular Assets, should you delete back faces or keep them?
polycounter lvl 5
I've noticed in a number of videos that some people like to keep the top, bottom, and back faces of a simple wall or floor when it comes to creating modular assets?? why would you do this when as far as I can tell, all it does is take up more lightmap uv space and just unnecessarily makes it harder to deal with. Whats wrong with just having the wall or floor just be a simple Plane?
Replies
On a serious note, I remember making walls but I deleted the top and bottom halves. This was because when I imported the object in Unreal Engine 4, it would sometimes show up invisible because the side that has the normal pointed towards the camera could be backwards. It got annoying having to rotate around the scene and having to search for planes so I just said screw it, I'll give it thickness.
For all Non-UE4 work, I basically delete all the faces that I wont need to show in a render shot. I'm even thinking of rendering environments where the entire back part of a building is removed!
IMO it's fine to leave it there for reasons JordanN stated. It's not the most efficient sure, but it's not going to be severe fillrate most of the time so the impact should be minor.
The smallest piece of foliage in any game is a lot more taxing on the rendering pipeline than a few unseen faces in wall kits anyway...
minute 25:00
If you delete one face of a box but leave the other 5, you have the same number of verts you had originally.
What if you delete the top and bottom faces, same number of verts.
Delete the back and top but leave the sides and front, same number of verts.
Delete both sides, the back and the bottom, but leave the front and top, finally you lost 2 out of 8 verts... (party horn)
Get rid of it all except for the front face and you've gotten the biggest savings you'll ever get, 4 out of the 8 verts remain (party horn and confetti)
So what are you really saving? UV space? UV verts? Shading verts? What is the real savings?
What are the effects of 2 sided rendering on your material? It renders ALL polygons that are assigned that material 2 times instead of once, which is probably more expensive than adding a polygon to cover up the back and rendering everything once.
Is that polygon useful in some way? Like Larry pointed out, does it help with lighting?
Do you have to place blocking volumes?
Can you guarantee that those polys really aren't needed and removing them will benefit the overall game in a significant way?
Is there a chance someone might place that prop and not cover up the open ends?
What looks worse seeing into the prop/void or starring at a cap?
Do they have to place a more expensive props over the gaps? That can cause you're layout to be more expensive.
Do the caps need materials, can they overlap existing UV's or use some tiny fraction of unused space?