optimizing polys

[Bobby]

Hi!
Here I would like you to give suggestions how to reduce poly count while getting rid of intersecting objects.
To start with,
http://lww.demon-host.com/index.php?page=properties&table=meshes&id=67
These chairs have 6-sided legs and 4 sided seat. Seat goes into legs so I think it\'s bad.
--------------#
---********#*********
---*---------#
---*-------#
---*-----#
---*---#
#####
---*
---*

* - seat
# - leg

When I perform boolean (difference only..) I get 200 polys out of 6 from the seat! That can\'t be.
Please if you know ways of how to reduce poly count or you know how many edges can cross until CS engine renders them bad (maybe I can leave it as is? Note here that Z positions are different) write here below. I am using Wings and Blender. I export objects between these two programs.

[aineko]

you can get it even more low polygon if you want.

take one box for the seat and legs and another, small box for the back of the chair.

then you have 12 Polygon. the bottom polygon of the chairs back is not really needed, so 11 Polygon.

Everything else is texture. partly transparent texture.

Code: [Select]


 _
| |
| |  <-- Box 2
|_|___
|     |
|     |  <-- Box 1
|_____|



You could use this for the LOD. if you\'re far away, you display only these boxes and when you get closer, you show more

[Bobby]

Thanks, aineko. I will try to finish my models using the LOD method.

Now if I may give noobs some points to keep in mind when making a mesh. I have noticed that some of the projects on the web site have got too much polys on a flat surface. For example: your flat, solid, square wall actually consists of two triangles. If you want to keep low on poly count, you can import to Wings and select the two triangles and press the backspace (dissolve) key. Whether it is a pentagon, hexagon, octagon or any other flat surface it is not needed to split it to triangles. For example: an hexagonal surface is made of 6 vertexes, 6 edges and 1 poly. And some of you make it 6 vertexes, 9 edges and 4 polys. There is no need to split every surface to triangles when local Z\'s are the same.

[Wedge]

There is no such thing as a square poly, it\'s all converted into triangles, so even if you made a \"square\" poly it would be split into two triangles when being rendered.

[Bobby]

then if i make such face

X---------------X
|\\................../|
|..\\......1......../.|
|....\\.........../...|
|......\\____/..2.|
|.4....X......X....|
|...../..........\\...|
|..../.....3.......\\.|
|.../...............\\|
|X/__________X

X - vertexes
_ / \\ - edges
.... surface

that means it does not have 4 polys but 6 (trapezoids 1 and 3 are converted to triangles?)
How it is done? When? So should I convert then every surface to triangles so CS engine will have less work rendering?

[Wedge]

There is always a line between two of those vertices in the 4-vertice poly, even if you can\'t see it.  It\'s not \"done\" at any time, it\'s always there.  All 3-d geometry is rendered as triangles because it makes the calculations infinitely simpler.  It won\'t make a difference if the line goes from the top left to bottom right, or vice-versa.  I\'d draw out the triangles on anything more than a 4-vertice poly though, just so you can be sure how it\'s calculating that.

I\'m not an expert on 3-d or anything, but I\'m pretty sure that\'s how it works at all levels.

[Bobby]

Wedge I was browsing through Blender tutorials and found this one:
http://members.yourlink.net/gruff/robot/index.html
In the end he writes the sentence:
\"Here I have activated the SMESH just to show you that these techniques work very well when working with Smeshes. This is because we have mostly quads instead of triangles and   a very low polygon count. \"
What do you think?

[Wedge]

That\'s a technique for getting lower poly counts in non realtime rendering.  If you were to export that model into a game and view it in wireframe, all those quads would be crossed into triangles.  I still think they are triangles anyway, that\'s just a better method for faking a hi-poly mesh for rendering.