View Full Version : BSP-Trees

11-23-2000, 04:14 AM

Can anyone explain me how I could use BSP-Trees.
I already found some tutorials about BSP-Trees. It's no problem for me to use them in a 3D-World where you can't go up or down, but I have no idea how I can use them if I have more stages.

Michael Steinberg
11-23-2000, 05:45 AM
What would be the problem?
It might be, that the tutorials you looked into just gave 2D illustrations. Then, do the same, but use 3D planes instead of 2D-edges to cut the world into pieces.

-Cut my world into pieces, this is my last bsp - http://www.opengl.org/discussion_boards/ubb/wink.gif

[This message has been edited by Michael Steinberg (edited 11-23-2000).]

11-23-2000, 10:53 AM
The trick is that you cut in different planes
for each stage.

Also, for 3D, you may wish to cut not just in
two, but in 8 (possibly axis aligned) pieces,
to make an octree.

Michael Steinberg
11-23-2000, 12:06 PM
What does that mean "to cut it in different planes for each stage"? Do you mean balancing of trees?

11-24-2000, 08:53 AM
Originally posted by bgl:

you may wish to cut not just in
two, but in 8 (possibly axis aligned) pieces,
to make an octree.

In my opinion there are only 6 axis but I think that would be the answer to my question.


11-24-2000, 08:59 AM
I said 8 pieces. As far as I know, there are
only three axis: X, Y and Z. These, in turn,
define three planes: YZ, XZ and XY.

Cutting along three planes generates 8 pieces
because each plane doubles the number of
pieces (sub-volumes) there already are.

11-24-2000, 11:07 AM
6D rendering :~~~

11-24-2000, 11:08 AM
Who will implement it first? http://www.opengl.org/discussion_boards/ubb/wink.gif

11-24-2000, 03:01 PM
You are right there are only 3 axis.
I meant you can test if one point is +x, -x, +y, ...
so we have 6 "axis" :-)

What I forgott was that the point has do be in an area, not on +x, -y and -z for example, so that you have to pass three leaves of the tree.

But now I hope I understand that correctly.