Lightmap size and increases in bake time and occupied texels

Unity Engine
1

Hi,

Can someone clarify is this is meant to happen and if so, explain the connection. Im using unity 2017.3.

I thought that changing the lightmap size is just about controlling how many textures get created, but it seems that changing this value changes the texel per unit as well.

If you look at the lightmap resolution (the checkers) using the scene visualizer you can see this happening. Im guessing i missed something as the docs dont seem to mention this. Also not every lightmap size makes a change, it seems to be based on a ratio with the LMap Res setting…for example

If you create a default flat plane and set it to static, set the lightmap resolution to 32, set the LMap size to 32, then increase incrementally and you will see the chequers alter in size, however this stops at a LMap size of 512…any higher and nothing happens.

Seems pretty odd.

much appreciated.

2

Yes, that’s correct (more or less).

Not really. But, it can happen. If you have one huge mesh, since its UVs can’t be split into multiple lightmaps, it can only get as much space as the maximum “Lightmap Size”.

I think that is where your confusion comes from. One mesh cannot occupy more that one lightmap. If lightmap size is pretty small (like, 32 is very small, I can’t really think of a use-case where 32 makes sense), then the maximum amount of texels one mesh can have is 32x32=1024. That is why you see texel density change when you switch to really low lightmap size values.

1 Like
3

That makes sense…thanks. :slight_smile: