[Polpolion]

Okay, I'm trying to teach myself how to turret my cap ships with Sketchup, set the hierarchy in truespace, and POF that stuff in PCS2 so I don't have to hire another person to do that for me. Except it's very confusing, and I don't think there are any sketchup guides for turreting and stuff. I did look at the sketchup help files, but to no avail.

First off, when I export my ship from Sketchup to 3ds and open it with truespace, it separates random spots on the ship into separate meshes. Is this okay? If not, what do I have to do to make it okay?

Now for the real issue: How do groups and components of sketchup translate into Truespace, and then into PCS2? Here's an example of what I have for a turret (I tried to color code the parts to make it simpler.)



The blue parts rotate side to side, the red parts rotate up/down and the green part remains stationary. What I did is I grouped the entire thing together as a single group, and made the blue and red parts components. Is this what you are supposed to do? Or am I supposed to make the entire thing a group, and then make the green, red, and blue parts different groups, and play with them in the hierarchy editor in Truespace?

Thanks for the help !

[Vasudan Admiral]

Well the first thing to get right will be the grouping - if you can export to a format which will keep the turret arms, base and hull as separate objects in the file, then you are good to go.

Here's a rough guide to how PCS2 will interpret object groupings. The one on the left is what you'd do if you set it up in TS, and the one on the right is how you could do it so that when 3d Exploration saved it, converting to cob should work.

(I would lvlshot this, but the tags seem to be b0rked.)


So can you find a way to control which objects are separated? I've never used Sketchup, so I can't help there.

[Polpolion]

Thank you! I shall use this as a guide in TS and save it for future reference as well! 

[blowfish]

Trust me when I say that getting the grouping correct may be the least of your problems when you try to get a model from SketchUp into the game.  Here are a few points you might want to take note of:

-In my experience, unless everything is textured, when the model gets into the game, it will appear to have no geometry, even if you look at it in wireframe in the lab.

-There is no way to get SketchUp to export its grouping correctly.  You must do all of the grouping in something else like TrueSpace.  Often, the two barrels of a multipart turret will show up as different meshes, so you have to locate and group them correctly.

-You have to move the axes of all submodels so that they look correct and rotate around the right point.  Everything looks really weird if you don't.  I'm not sure how to do it though.

Overall, I think that getting models made in SketchUp to work in game is a complicated and somewhat delicate process.  It takes some experimentation to get it right.

[Vasudan Admiral]

From the sounds of it, getting the groups to export correctly is the single most important thing there, as textures are a given - you'll have that problem in any 3d program upon converting to POF, and you can only do object centres (which is nice and easy) if you have correctly separated objects anyway.

[blowfish]

Getting the grouping right in TrueSpace is pretty easy.

But you have to get the axes of the turret arm right where you want them to rotate around, which requires positioning them manually.  For the rest you can just move the axes to the center of the object.

[Vasudan Admiral]

Yeah I know - axis stuff is easy. But if Sketchup just exports random chunks of mesh to different objects as TS sees them, you have a major headache. Someone is going to need to work out exactly what to do in order to control how Sketchup exports objects. If you can't control this process then you'll have to create each separate object component of the model and export them separately before recombining them in TS into a hierarchy.

[blowfish]

SketchUp exports each individual mesh as a separate object, not chunks of mesh.  If a turret has two barrels that are not connected by any geometry, than they will show up as separate objects in TrueSpace.  It is pretty easy to group them, figuring out what is what is the hard part.

[Polpolion]

What exactly is the mesh? Is it just chunks of the model? Is there anything preventing me from simply combining the meshes that I want to together into one? 

[blowfish]

A mesh is a bunch of polygons that are all connected.  SketchUp will export each individual mesh as a different object, and you must group the meshes in TrueSpace.  It might look something like this:

-Detail0
    -SomeMesh
    -SomeOtherMesh
    -turret01-base
        -BigTurret05
        -turret01-arm
            -SomeMeshThatIsOneOfTheTurret'sBarrels
            -AnotherMeshThatIsTheOtherBarrel
    -turret02
        -smallturret03
        -somelight


If a component only contains one mesh, then the name of the mesh will reflect the name of the turret.  If it contains multiple meshes, they will be named something weird.

[bizzybody]

First off, when I export my ship from Sketchup to 3ds and open it with truespace, it separates random spots on the ship into separate meshes. Is this okay? If not, what do I have to do to make it okay?

If you're having problems with things like a chunk of your hull importing into trueSpace as a separate object, leaving a faceless hole in the in the other part of the hull, then you're experiencing geometry problems in Sketchup.

From some of the models I've seen people do with Sketchup, it's apparently easy to inadvertently get edges and vertexes occupying the same coordinates without them being connected.

Think of a pair of playing cards leaned up against one another. They're two separate objects yet their upper edges are practically in the same space. Apply a bit of glue and they're a single object.

I've seen this same problem with just about every format trueSpace can import. trueSpace has always been designed to work with solid models, going all the way back to its early days as an Amiga program. (Thus the funky UI, blame it on Amiga!) Several other 3D programs can take a mess of one-sided polygons with their edges "leaned up against each other" and manipulate the collection of bits flying in formation as if they really are a single object.

How does Freespace handle non-solid meshes? Does it choke on them or will it go ahead and work? If it can't tolerate non-solid meshes, I suspect that's why trueSpace's .cob format was the original format of choice for modders- because you cannot make a non-solid simple object* in trueSpace without deliberately deleting a face.

*Well, in 3.2 and earlier you can, if you distort non-triangles too far you can "rip holes" in the mesh. 4.x and later are much better at handling extremely non-flat polygons with 4 or more sides.

[Vasudan Admiral]

TS can make holes in a mesh if you glance at it wrong - the disconnected geometry you describe is usually because of the TS import rather than the mesh actually being disconnected. There's no way to easily fix it either as there is no basic 'Remove Doubles' function, so the inability to handle non solid objects well is certainly not a positive point. It's one of the single most annoying things about TS aside from the whole barely being able to do anything aspect of it and the endless crashes.

Freespace can handle non solid objects just fine, but without careful use of the technique it becomes bad modelling practice to build a hull out of disconnected and intersecting objects. Such things cause all sorts of unnessecary instabilities in the model, so it's an absolute must to keep the mesh neat and tidy. You'll have many mesh problems long before you get it in-game.

Anyway, if sketchup just separates continuous meshes into different TS objects that's ok. Not great by any means, but workable.

[Scooby_Doo]

Also a little hint, when you've got a turret looking the way you want, in truespace, select the entire turret and export it to a cob file.  You can latter import that turret when you want to reuse it.  You'll just have to renumber it.