Using displacement surfaces as room curves

I am getting into using displacment surfaces for indoor
architecture. I am replacing curves in corners of rooms with
displacement surfaces (1 displacement surface instead of 8 brushes that
form a concave curve). From what I've read, using one
displacement surface is much easier on the fps than making those 8
brushes into one func_detail.

Question 1: Is it easier on the fps to do 2 displacement surfaces each with a power of 2 instead of one with a power of 3?

Question 2: For convex curves, is it better to have a single
detail brush with 10 sides (8 for a curve, 2 to give it a backing) or
to make one displacment surface with a power of 3, or two displacement
surfaces with a power of 2?

Just trying to figure out how much better for fps speeds displacments are relative to func_details...

Hey Imbrifer, are you the same Imbrifer from FF?

Displacmets will help with FPS, but I doubt you'll notice unless there are lots of curves in a small area.

2.) first of all, you dont need the two extra brushes to back the
curved wall, but if you do want to use that method (I assume so you can
make the curve a detail brush) you can use two world brushes with the
nodraw texture on them.

and

2 displacements to the power of 2 would be 2² = 4 and one displacement
to the 3rd power would be 1³ = 3, if that is how they work, then the 1
to the power of 3 is best.

<DIV class=quote>
<DIV class=quotetitle>? quoting DrGlass</DIV>
<DIV class=quotetext>one displacement to the 3rd power would be 1<SUP>3</SUP> = 3</DIV></DIV>

Er, what?! 1<SUP>anything</SUP> = 1 (well, anything greater than 1).

I don't know how displacements are meant to (if they do) "save on FPS", but logic dictates that a 3rd power surface has the same number of triangles as 2 2nd power surfaces (2 x 2<SUP>2</SUP> = 2<SUP>3</SUP> = 8). To be honest, with such a low power being used you shouldn't get any noticeable improvement in performance over using a func_detail/brush, unless there are hundreds of these things in the same room. As ever, the best way is to try it and see :razz:

DrGlass said:
one displacement to the 3rd power would be 1³ = 3

Er, what?! 1^anything = 1 (well, anything greater than 1).

ouch, no wonder I'm an artist.

Lep, you forget that it is 2^power in both x and y directions. So
2 2² disps = 2*(2²)*(2²)*2 = 64 tris, and 1 2³ disp =
1*(2³)*(2³)*2 = 128 tris. Naturally it would be easier to
create the 2 power-2 disp since there are less nodes to deal with in
manipulation. But I doubt it would improve fps by much if any
considering that even 64 tris is four times what you would have used
just doing simple func_detail's. Plus doing the func_detail is
1,000,000 times easier.

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To get something to work, sometimes you just have to beat your head against the wall longer; the skin grows back, but the brick doesn't.

Source hates soup!

Whoops, good point :redface: The difference will be in the width then, but again there's not that much in it (unless you've got loads of these around), so it's down to what's easiest. In fact, having all these displacement surfaces mean there are more 'actual' surfaces in your map, and if you use a special texture on them (e.g. with bump mapping or reflections) that could possibly kill FPS (swap buffers?); I'd just stick with many-sided cylinders and the like personally :smile:

Also I believe displacements don't VIS block, so you'd probably get fps
drops in those area's because you can see into other area's of the map.

Take Lep's advice, stick with the solid brushes.

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Ham and Jam Contributor
http://www.hamandjam.org

'Get your stinking paws off me, you damned dirty ape!'

Also I believe displacements don't VIS block

No, no they don't. I know a fool who made a cave out of displacements
thinking they could block VIS and then had to cover the whole thing with a
box which took ages and killed the fps. Guess who the fool was?

me :sad:

Yeah I kinda called that one from the start Andrei :smile:

I think just go with displacement, sence they are better optimised in Hl2 than world brushes.

Until Later...

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Dark_Kilauea
DVS Administration
http://www.dvstudio-production.com/

I think just go with displacement, sence they are better optimised in Hl2 than world brushes.

You obviously don't read the other posts before posting. You are incorrect.

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Ham and Jam Contributor
http://www.hamandjam.org

'Get your stinking paws off me, you damned dirty ape!'

of course I read, I also read somewhere that valve did a lot of
optimization of displacements... I dunno, could be worng.

Until Later...

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Dark_Kilauea
DVS Administration
http://www.dvstudio-production.com/

They are optimized, which is what makes them great for outdoor area's
since they are easy to compile because they aren't compiled like
brushes during VIS. However their drawback is that they do not block
VIS, hence the need for blockers behind the displacement surfaces. If
your just making a corridor with a curved edge use brushes, the engine
is so frickin powerful I doubt they are going to make that much of an
impact on the fps.

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Ham and Jam Contributor
http://www.hamandjam.org

'Get your stinking paws off me, you damned dirty ape!'

its true displacements render faster than world-brushes, but that is compared to their equivalent shapes.

say you have a displacement made out of 24 triangles, then that will
render faster than 24 world-brush-triangles. but it wont render faster
than 3 world-brushes. (more or less than 3)

you should just stick to detail brushes, they not only render faster
(as long as you keep their number down as i already explained above),
but you also can get the benefits of smoothing groups (allowing for a
nicer rounder look)

Hmm, I think I understand. So if I have a power-of-3 displacment
(112 triangles) and one func_detail which is 8 five-sided brushes (40
triangles), it would be better to go with the func_detail?

Careful mapping can avoid the 'seeing-into-other-areas' problem.
The last map I made I didn't know displacements don't block VIS - so
the bastard took 12h+ to compile with sloppy VIS work - I'm working on
my optimizing skills and I'll go back to it next week or so.

I have a map with a whole bunch of displacements (it's a remake of
2morfort1_1) and I have just a bit of detail left and the damn thing
compiles in under 5 minutes with a batch file - no joke

And yes, I am the Imbrifer on the FF forums. There is only one Imbrifer. :smile:

Why you would have a situation where you are replacing displacements
with 5 sided brushes is beyond me, and its 128 not 112, but yes the
func_detail will most likely render faster. But since they will
probably both take very little time, the displacement may have other
benefits like ease of editing.

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To get something to work, sometimes you just have to beat your head against the wall longer; the skin grows back, but the brick doesn't.

Source hates soup!

What I'm doing with displacements is making the 'inside' of
arches. The five sided brushes are eight wedges which all meet in
a corner, while the displacement is a surface molded to be the arch
which the wedges create (think 1/4 of the outside of a cylinder).

So the way I see it, the benefits of detail brushes are ease of
editing, and faster rendering. The benefits of using a
displacement surface are... well.. the lighting looks better, but you
can always use smoothing groups on the detail brushes...