Polyloop - 3D & 2D Forums - View Single Post

pavroza · 31st December 2006, 12:53

Hi, thank you for your replies.

Yes, it looks like "decimantion" with 1.0 values could do that task. It makes
triangles for all quads in an object. I would prefer all the triangles to be generated the same way for all quads (always from the upper left corner to the lower right corner of the quad or from the upper right corner to the lower left corner) but it could be ok. Thanks again!

As regards the previous question about why I wanted triangles and not
quads:

I want my models to use triangles because I want to make 3D models for
real-time applications (mostly video-games and simulation).
Quads are a "compact" way of transferring information to the video card but they also have a big problem: many 3D engines need triangles.

Non-flat quads (when the 4 points are not located into a single plane) ,
or concave quads (when two edges make angles bigger than 180) coud generate visualization artifacts wrong colour distribution or not be seen at all (low level APIs like OpenGL require to tesselate non-convex shapes)

And finally...what's the best shape to approximate the shape of a triangle??
a quad? or a triangle?

hehehee (just joking).
Triangles are equivalent to pixels in 2D, the minimal shape from what you
can build every object you can imagine.

Perhaps my needs are a bit specific, I don't make nice organic models with
subdivision surfaces

Well, thanks again to everybody!

31st December 2006, 12:53	#5 (permalink)
pavroza Vertex Join Date: Dec 2006 Posts: 5	Hi, thank you for your replies. Yes, it looks like "decimantion" with 1.0 values could do that task. It makes triangles for all quads in an object. I would prefer all the triangles to be generated the same way for all quads (always from the upper left corner to the lower right corner of the quad or from the upper right corner to the lower left corner) but it could be ok. Thanks again! As regards the previous question about why I wanted triangles and not quads: I want my models to use triangles because I want to make 3D models for real-time applications (mostly video-games and simulation). Quads are a "compact" way of transferring information to the video card but they also have a big problem: many 3D engines need triangles. Non-flat quads (when the 4 points are not located into a single plane) , or concave quads (when two edges make angles bigger than 180) coud generate visualization artifacts wrong colour distribution or not be seen at all (low level APIs like OpenGL require to tesselate non-convex shapes) And finally...what's the best shape to approximate the shape of a triangle?? a quad? or a triangle? hehehee (just joking). Triangles are equivalent to pixels in 2D, the minimal shape from what you can build every object you can imagine. Perhaps my needs are a bit specific, I don't make nice organic models with subdivision surfaces Well, thanks again to everybody!