Displacements: Few @ Power 4 vs Many @ Power 2

[the DT's]

I've looked around for a while but wasn't able to find a satisfactory answer to this:

Does it make a difference in performance to use few displacement surfaces at high power vs many at lower power, if either way uses roughly the same number of triangles?

If so, is the difference significant enough that I need to be really anal about size of my displacement surfaces?

 

[littleedge]

The only thing I know about Power 4 Displacements is that if a bunch of Demomen launch their stickies onto Power 4 Displacements and explode them, it's more likely to cause crashes. It's all about vertex DENSITY. If you have a large Power 4 Displacement, go for it. If it's a tiny brush and there's a bunch of vertexes around, make it bigger or make it a lesser power.

 

[Fruity Snacks]

I'd stick to many 2's.

If you go up to 4 and somehow did something to screw with source, you get a rocket blast there or a couple of stickies to blow up on that brush and you could crash the map.

Its best to stay with many 2's. 3 is acceptable if you know what you're doing.

(**this is all based on what I've been told in the past)

 

[A Boojum Snark]

Smaller 2s are easier to work with as far as the base brushes are concerned with. Beyond that there is no performance difference besides the aforementioned crashed with small, dense, power 4 displacements when impacted by a physics object (ragdolls, dropped weapons, stickies, grenades, debris).

 

[Randdalf]

You will almost never need to use a power 4 displacement, I mainly use 2s for larger out-of-bounds areas with a 3s in high detail areas

 

[MangyCarface]

Smaller 2s are easier to work with as far as the base brushes are concerned with. Beyond that there is no performance difference besides the aforementioned crashed with small, dense, power 4 displacements when impacted by a physics object (ragdolls, dropped weapons, stickies, grenades, debris).

this has to be why my first map always crashed....

 

[Ravidge]

I'm pretty sure that having a lot dense displacements shoots the filesize to the moon with light-data. I have nothing to back this up though, It's just a hunch I have since my displacement oriented first alphas has sometimes reached 50mb.

 

[the DT's]

Thanks so much guys. I was going a little nuts at times trying to avoid using several disp's to cover a single larger area, thinking it might be bad for some reason.

On the one hand, it turned out to be good practice at making cleaner geometry, but on the other it's good to know that the option's there if I should need it for something a little more complicated.

 

[A Boojum Snark]

You should open up the dustbowl VMF that comes with the sdk, and look at how valve does it It's virtually nothing but 200~300 unit power 2 displacements.

 

[WastedMeerkat]

You should open up the dustbowl VMF that comes with the sdk, and look at how valve does it It's virtually nothing but 200~300 unit power 2 displacements.

Yeah I've been told to make a bunch of 256x256 power 2 displacements and stitch them together. It's supposed to be about the right size to look good and not be too jagged.