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Face select/twoside problems

Posted: Tue Dec 14, 2004 6:55 pm
by bannerboy
ok, is there a way to apply the twoside property to multiple faces at one time? and does the twoside property slow down live3d

Posted: Tue Dec 14, 2004 10:24 pm
by ideasman
select all to apply to
Select the 2 sided face so its active,
press the copy draw mode button.

Posted: Wed Dec 15, 2004 1:53 am
by bannerboy
thanks, I never would have thought to do that my self.

Posted: Wed Dec 15, 2004 10:30 am
by joeri
2 sided faces slowdown the realtime engine.
I even think it's converted to 2 single sided faces !!!

Posted: Wed Dec 15, 2004 2:35 pm
by halibut
joeri wrote:2 sided faces slowdown the realtime engine.
I even think it's converted to 2 single sided faces !!!
Afaik, this is how all realtime rendering works. Double sided faces only exist if two faces are defined (I am thinking vrml here).

Posted: Wed Dec 15, 2004 4:42 pm
by z3r0_d
halibut wrote:
joeri wrote:2 sided faces slowdown the realtime engine.
I even think it's converted to 2 single sided faces !!!
Afaik, this is how all realtime rendering works. Double sided faces only exist if two faces are defined (I am thinking vrml here).
in opengl you can turn on/off twosided drawing as well as specify which side is the side to be drawn [by clockwise or counterclockwise verts on the screen]

however, the driver can implement it any way it wants

Posted: Wed Dec 15, 2004 6:48 pm
by halibut
z3r0_d wrote:
halibut wrote:
joeri wrote:2 sided faces slowdown the realtime engine.
I even think it's converted to 2 single sided faces !!!
Afaik, this is how all realtime rendering works. Double sided faces only exist if two faces are defined (I am thinking vrml here).
in opengl you can turn on/off twosided drawing as well as specify which side is the side to be drawn [by clockwise or counterclockwise verts on the screen]

however, the driver can implement it any way it wants
So, will a 2 sided mesh take around twice as long to render as its single sided equivalent or not?

Posted: Wed Dec 15, 2004 9:24 pm
by ideasman
It makes since that it takes longer0

Double fill rate, no backface cilling

Posted: Thu Dec 16, 2004 4:08 am
by z3r0_d
halibut wrote:
z3r0_d wrote:
halibut wrote: Afaik, this is how all realtime rendering works. Double sided faces only exist if two faces are defined (I am thinking vrml here).
in opengl you can turn on/off twosided drawing as well as specify which side is the side to be drawn [by clockwise or counterclockwise verts on the screen]

however, the driver can implement it any way it wants
So, will a 2 sided mesh take around twice as long to render as its single sided equivalent or not?
depends how much wasn't drawn by the single sided equlivent, and a bunch of stuff relating to the graphics card

so, the answer is it can be, but it will not always be signifcant

Posted: Thu Dec 16, 2004 12:10 pm
by joeri
halibut wrote:
z3r0_d wrote:
halibut wrote: Afaik, this is how all realtime rendering works. Double sided faces only exist if two faces are defined (I am thinking vrml here).
in opengl you can turn on/off twosided drawing as well as specify which side is the side to be drawn [by clockwise or counterclockwise verts on the screen]

however, the driver can implement it any way it wants
So, will a 2 sided mesh take around twice as long to render as its single sided equivalent or not?
There is no way to look at both sides of a triangle. So the onscreen drawing speed will stay the same. But... for all the logic it's an extra triangle, so determing if it should be draw will take time, if it's a colidable plane then it will eat time in the colision detection module. etc.

Posted: Thu Dec 16, 2004 8:49 pm
by halibut
joeri wrote:There is no way to look at both sides of a triangle. So the onscreen drawing speed will stay the same.
Ohh yeh :D

Posted: Thu Dec 16, 2004 9:18 pm
by theeth
joeri wrote:if it's a colidable plane then it will eat time in the colision detection module. etc.
Unless there's some optimisation for two sided faces (would only be logical don't you think?).

Martin

Posted: Thu Dec 16, 2004 9:27 pm
by joeri
I know Erwin and Gino, logic has nothing todo with it.

Check the near sensor... and you will start to know what I'm talking about.

Posted: Fri Dec 17, 2004 12:29 am
by theeth
I won't touch C++ code unless I'm forced too, so I'll pass.

Martin

Posted: Fri Dec 17, 2004 12:50 pm
by joeri
theeth wrote:I won't touch C++ code unless I'm forced too, so I'll pass.
Martin
I can understand that.

I made a little pacman game in blender. Should work, how hard can that be?
Have some pills with a near sensor and if pacman is near the pill dies and adds a point.
Only it was very very slow.
How long can a manhatan test take? it's only 144 pills.
Turns out the near sensor is implemented as a collision in solid with a sphere of a given near size. Logical? sure, it's beautiful code, who cares about performance?

" would only be logical don't you think? "
Right. That's what you'd think. But that has nothing to do with how it's done. :)