how do i make meshes hollow ?

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1

hey, i have a little forest image here

http://ic1.deviantart.com/fs5/i/2004/272/4/2/forest_WIP_by_nehpets.jpg

and the tops of the tree’s are a buncha sphere’s…and everytime i duplicate the group to make the forest bigger and try to render…i get lots of freezing.

soooo…

i was wondering if i could take the group of meshes that make my tree tops and hollow them out to reduce the poly’s that you don’t see on the inside…and improve render time

2

Oooo, don’t do that. Just use Dupiverts. That way you can have one mesh and a bunch of other verts that render the same as that mesh but take up as much memory as a vert does.

Do this. Add a plane. Select your Treetop, then shift+select your plane. Now hit Cntrl+p and make parent. Now select the plane, hit f7 and click the Dupliverts button.

Now every vertice on your plane will spawn an instance of your treetop. You can add more vertices to your plane with subdivide or whatever, and move the vertices wherever you want.

3

Youcannot make them not hollow

4

Hypotheticaly, there is a way to make them “hollow”. (Don’t use it for this scene though).

While the proper solution is Enzoblue’s way, it is possible to hollow out the trees without remodeling them.

Assuming you start with a bunch of intersecting spheres;
You can use the new “clip selection with z buffer” work mode in the latest CVS releases. With it, it’s possible to select only the verts on the outer surface, rotating the mesh as you go, and then swap the selection and delete the center verts. Because the faces only intersect, there will be some holes, but they can be closed.

tought it posed an interesting puzzle.

5

thanks Enzoblue !!! thats just what i needed…except now i have the problem with them all facing the same way…hmm, maybe if i had a group of tree’s dupliverted on a plane that wag big ? ill have to test :]

6

Also CSG union would remove interior verts… hypotheticaly. Blenders internal CSG implimentation usualy creates more verts then it would get rid of. You could try the Megabool script availible in the python forum though. It gives good results and the only problem I’ve had with it is that it doesn’t always make enough faces.