Collision using sub-parts?

[chip]

Before I try an idea I have, I figure it's better to see if anyone's already invented this particular wheel.

Using the primitive squares from Alice's stock inventory, I've tested a "collision hull" surrounding the lake in my world. When the character steps (approximately) off the shoreline, she drops about a meter into the water and can then "wade" around in the lake. Leaving the lake through the wall, she rises back to ground level -- a very primitive form of terrain-feature response.

But using the rather small squares to line the entire shore of a rather large lake causes Alice to choke on saving the world -- out of memory error. I guess some optimization of Alice in that regard would be helpful, since the world isn't all that complex. Yet

So my idea is to build a "fence" for the lake in Blender and import it, then use the subparts as collision objects. But do the subparts have individual centers (pivots) that I can reference in my collision routine? I haven't yet used multi-part models, so it's terra incognito for me. Any insight would be appreciated.

[sfunk]

well you could actually just use on large object and use the functions whether an object is in front of behind left of right of which gives a pretty good collision method, so if the lake is a pretty straight5 edge it would be pretty easy to implement this, look at damerias maze game if you want to try this out

[chip]

That's where I looked first, actually. The problem is that the methods dealing with relative position are all based on object pivots, not the geometry itself. So if you have a large and irregular area (like a lake) to detect collision in, you need lots of smaller objects acting as "sensors." This works, I've already done a proof-of-concept with individual squares from the Alice library, but they're too small & take forever to set up.

So I'm looking to make it more efficient and less trouble to implement by using imported geometry, which can be tailored to fit the landscape, since that was also modeled in Blender.

So far I'm running into probs with getting the meshes into Alice as sub-parts, some issues with the way various translators deal withe the Blender mesh. I'll post here later if I find a solution.

[sfunk]

well I know you can create sub parts real easily in google sketch up

[chip]

Creating the sub-parts isn't hard from Blender either, I have two different exporters that can do that. The problem has been finding a method that also preserves the object pivots. In my exported ASE files, all the subparts are in the right place, but their pivots have all been moved to the world origin, which isn't useful for what I want to do. If I use options that keep the sub-parts pivots where they belong, all the sub-parts get clustered on the world origin, which is also no joy. Catch22.2

[sfunk]

yeah I know what you mean, the only way to create perfect sub part pivot points is to create every object on the origin in either blender or sketch up, 3d max I think allows perfect pivot points if you ever used that