Splitting up a large mesh

Hi all,

I’m real new to Blender so go easy on me!, currently using 2.49.

I have a large landscape made from 1 mesh, also ‘objects’ are placed on the mesh like tree’s etc. etc.
I wish to use this scene in a pc project but I need to cull what gets rendered.
My solution to this is to “somehow” cut the landscape up into 3d cubes and export all the vertices/textures within each as a separate object. Then I can simply check “if cube 1 is on screen render all it’s contents” and so forth. This would be a lot more efficient by having the landscape cut up into zones.
My question is how the heck do I do this in Blender? :slight_smile:

Any help appreciated



Well if there are different items in one mesh you can select one of the vetices and then press Alt+L and then press P and removed the selected… You can move these separate meshes onto one area…

Hi Blendface.

Sorry, you’ll have to go through it 1 step at a time :slight_smile:
I need to keep everything in it’s same space coordinate. What about the landscape that is 1 mesh and goes through many of the cubes?, how do I “cut” that at points where cubes join?
I need a method that’s easy and fast, because the level will be sent down many times to the project.


You could probably box select instead then by pressing B

So If I box select (say from above looking down) do I then have to delete everything else? i.e. so I just have my area selected and export that?
If so will it deal with faces potentially being cut where the landscape mesh overlaps 2 cubes?
Is there a way I can automate this? i.e. it goes through each ‘cube’ and exports it rather than me selecting it 1 by 1?

Thanks for your help


Hi Mark,

I’ve been doing a lot of this type of object splitting in a current project. Here’s a quick list of steps:

Be in edit mode.
Press F9 to get your editing buttons up.
Go to selecting faces mode (make sure “occlude background geometry” is switched OFF if you’re not in wireframe view).

1 Select a chunk of faces.
2 In you buttons window, under Mesh Tools, click Split.
3 Put the mouse back in the editing window and press P.
4 Click Selected (once you’ve done this once you can just press enter the next times as long as you don’t move the mouse after you press P).

That’s it. Go back to step 1.

Hey thanks!

I’ll give that a try!



Are you trying to optimize how much gets drawn on the screen in your PC project? If so, most 3D engines will do that for you, ie, they will disregard anything not seen by the camera (they won’t do lighting calculations except for reflection and light sources, they won’t render textures, etc). I’m pretty sure XNA uses this type of optimization, if that’s what you’re using, and since XNA is based off of DirectX, DX should as well. I could go off on a tangent :slight_smile:

[lightbulb edit]: Furthermore, if you really do need to do fancy math, you could just calculate yourself which objects are in view of the camera using some basic trig… but trig is beyond me!