View Full Version : Need help with roller coaster model

06 June 2005, 11:13 PM
curves extrusionI thought this was going to be easy, but I can't figure this out.

I'm trying to make a section of a steel coaster track. I have my parts built.

Now the problem is this:

I would like to combine the two (I'll make another, the screen shot only shows one) rail curves and main rib circle into one object so when I extrude them along the guide curve everything lines up.

Is this even the right way to go about this? I'm afraid I don't have much XSI experience, I'm used to Maya. :)

06 June 2005, 05:05 AM
yeah why not?

u can create polymesh from curves and extrude it along the track's curve.

06 June 2005, 04:58 AM
Well, when I convert the curves to poly mesh using Model>Create>Poly. Mesh>Curves to Mesh and then select the new poly mesh and try to extrude it via Model>Create>Poly. Mesh>Extrusion via Curve or even Model>Create>Surf. Mesh>Extrusion via Curve I get the following error:

ERROR: Invalid object(s) have been provided for group 0.

What's up with that? :head scratch:

06 June 2005, 05:43 AM
extrusion along curve only works if u r selecting the polygons on the mesh(using the "U" key), i think. u can't extrude the whole mesh.

what i would do in ur case is, keep the mesh unfreezed after curves to mesh, so that i can adjust the subdivision later on. Then i'd do a "deform along curve" onto the mesh. Now, i can adjust the length of the rail by tweaking the "scaling along curve parameters" under the deformation property dialog, and at the same time adjust the subd of the mesh found in the curve to mesh property dialog so that it'll look smooth all the way.

once u r satisfied with how the mesh looks, freeze it. otherwise, u can still alter the curve and so on.

06 June 2005, 06:33 PM
hmmm I'm getting the same error.

06 June 2005, 07:13 PM
Tocpe - is your image from Invader Zim? Looks like it..

06 June 2005, 11:46 PM
Tocpe - is your image from Invader Zim? Looks like it..
My avatar? Nope, Foamy & Pillsy:

06 June 2005, 01:41 AM
anybody else have any ideas? I'm stuck :(

06 June 2005, 03:01 AM
Nice! I once tryed this as well and I failed :(

06 June 2005, 05:16 PM
Anyone else know how to do this? I'm kinda stuck. :(

06 June 2005, 05:20 PM
I'm not 100% sure I get what the problem is.
assuming that your problem is with the second circle (the one distant from the world center) lining up with the curve when extruded, instead of mantaining the offset...

have you tryied freezing its translation (translation, not the operators stack) before the extrusion?

06 June 2005, 06:58 PM
Well, basically I'm just trying to make a roller coaster track. :) This is the method I came up with, but I'm not sure it's the right way to go. Since I'm still new to XSI, I'm still learning it's modeling workflow. So really any help on the best technique to extruding the three circles (The main tube & the 2 "rails") along a path is what I'm looking for. :) But if that's not the way to do it in XSI, I'm "all ears" for new methods.

In Max & Maya there are ways to "attach" difference curves to form one "master" curve that could be extruded along a path. That's what I was trying to do, but if it's not the best way, or even possible in XSI, I'd appreciate knowing the proper way.

CGTalk Moderation
06 June 2005, 06:58 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.