Face select/twoside problems

bannerboy · Post by **bannerboy** » Tue Dec 14, 2004 6:55 pm

ok, is there a way to apply the twoside property to multiple faces at one time? and does the twoside property slow down live3d

ideasman · Post by **ideasman** » Tue Dec 14, 2004 10:24 pm

select all to apply to
Select the 2 sided face so its active,
press the copy draw mode button.

bannerboy · Post by **bannerboy** » Wed Dec 15, 2004 1:53 am

thanks, I never would have thought to do that my self.

joeri · Post by **joeri** » Wed Dec 15, 2004 10:30 am

2 sided faces slowdown the realtime engine.
I even think it's converted to 2 single sided faces !!!

halibut · Post by **halibut** » Wed Dec 15, 2004 2:35 pm

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).

z3r0_d · Post by **z3r0_d** » Wed Dec 15, 2004 4:42 pm

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

halibut · Post by **halibut** » Wed Dec 15, 2004 6:48 pm

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?

ideasman · Post by **ideasman** » Wed Dec 15, 2004 9:24 pm

It makes since that it takes longer0

Double fill rate, no backface cilling

z3r0_d · Post by **z3r0_d** » Thu Dec 16, 2004 4:08 am

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

joeri · Post by **joeri** » Thu Dec 16, 2004 12:10 pm

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.

halibut · Post by **halibut** » Thu Dec 16, 2004 8:49 pm

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

theeth · Post by **theeth** » Thu Dec 16, 2004 9:18 pm

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

joeri · Post by **joeri** » Thu Dec 16, 2004 9:27 pm

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.

theeth · Post by **theeth** » Fri Dec 17, 2004 12:29 am

I won't touch C++ code unless I'm forced too, so I'll pass.

Martin

joeri · Post by **joeri** » Fri Dec 17, 2004 12:50 pm

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.