Amount of displacements

Well, my map is going to have alot of displacements, since I am using
them for pretty much all of the walls (mountains) and the ground (who
doesnt use them on natural ground?). Since that is alot of the map, my
question is: Is there a limit to how many displacements I should be
using. I would imagine they are made to be used in larger amounts, for
better looking stuff, but you never know. I mean, they made a carve
tool...

Anyways, thanks in advance for the help.

i wouldn't worry about the strain that displacements will make on the engine, though i would worry about not having good visblocking behind them.

Good visblocking as in the thing ReNo mentions in the displacement tut?
What does that doe, exactly? Do I just place something like a nodraw'ed
box directly behind the displacement brush, as well as putting nodraw
on all sides of the brush not being a displacement?

Actually I didn't mention it, but Lep added it as a foot note :biggrin:

You kinda have the right idea there. VIS blocking is the act of placing
brushes so as to stop VIS from thinking it can see things it can't.
World brushes block VIS, but brushes that have a displacement surface
on them do not. For this reason if you have a large hill in the middle
of you map made from a displacement surface, you could be on one side
of the hill and not see anything on the other, yet everything over
there will still be rendered. If you then put a big brushes inside the
hill it would block VIS, and if you placed it intelligently then it
could mean nothing on the other side of the hill will be rendered.
There are plenty of articles online that talk about how VIS works,
often on the topic of hint brushes. I suggest you give them a search if
you are interested in knowing the fine details :smile:

Edit: ReNo explained everything very clearly.

only problem is that displacment adds to your maps bsp size. I
have a map with... maybe 25-35 displacments and it is almost
35mb! so keep that in mind.

it is almost
35mb! so keep that in mind.

Lol, dm_haul is in alpha stage and is 17mb large! Me thinks i'm gonna beat your measly 35mb :smile: .

The limit is 2048 displacements I think... I'm quite sure there was a thread on the subject earlier.

Displacements are incredibly cheap to render, when compared with BSP geometry.

Ah, I think I get you. So, if I did have said hill, would I have to put
a brush underneath it, or through it (filling up the gap inside, not
through the top or sides)?

Also, if I use displacements for something like a mountain that is the
edge of the map, do I have to VIS block that? Because there is nothing
behind it to get rendered.

Yes, you have to make sure that your map is completely sealed off with
normal brushes. You can't have a displacement surface be the
onlything between inside your map and the void.

Well, putting a skybox around it counts, right? I didn't plan to just
leave it open. But I guess if I have a skybox, the brushes behind the
displacement would still be used to block the skybox, yes?

Edit: I took your advice ReNo, and read up on VIS blocking, and while
doing so managed to read up on Hint brushes as well. Alot of things
said that big open areas are a no-no, but I plan to have an open field
type area in my map, but wasnt planning on having big walls and such in
it. Is there really a good way to optimize a bigger, more open area?

BTW, am I starting to ask too many questions for one thread? I dont
like making alot of topics, but if it is better, I guess I can do that.