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Trying to build curved ramps in Gmax - HELP!

Started by nathkel, March 17, 2013, 09:50:49 AM

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nathkel

Building a straight 3D slope in Gmax is easy. But all my attempts at building a CURVED ramp is failing. I have read all the tutorials available for creating structures for SC4, but i inevitably run into problems for this project.  ()what()

Here's what i've tried:

1. Spline extrusion: I created 3 straight lines in Left perspective, connected the vertices, applied an Extrusion modifier, Then, to make several faces, i tessellated the poly 2 or 3 times. When i applied the Bend modifier, however, no matter what i tried, i could not line up the ending vertices even on a 90-deg. bend. They ran over a small amount. Since i had so little control over the radius and bend pivot, i abandoned this method.

2. Arc Extrusion 1: I created an arc spline, applied an Edit Mesh modifier, changed the Thickness to 16 m (the width of a SimCity roadbed), selected the top faces of the curve, and went to Select-and-Rotate mode. However, when i rotated the vertical angle, it moved the vertices out of alignment on the XY plane. I had to go bsck and manually align the top vertices with their lower counterparts. This somehow skewed the arc out of the original angle.

3. Arc Extrusion 2: Tried the above again up to setting the base vertices. Then i looked in the Gmax help file, and following the instructions, tried to link a Plane Angle manipulator to the top faces of the arc mesh. Didn't work.

If anyone can help me, please do. I feel like i'm re-inventing the wheel -- surely someone has done this before in Gmax, or at least has the expertise enough to solve the problem. Ideally i want to divide the ramp into 8 or 12 vertical pieces, then bend the ramp around. I'll be making curved berms for 90, 45, 18.8, and 71.1 degrees.

If you can provide pics, we can make it into a tutorial. Otherwise, a step-by-step answer will suffice.

callagrafx

Here's a hint... loft  :thumbsup:

All you have to do is draw your curve path, then a cross-section of what you want to curve.  Select the curve path and under the geometry rollup there's an option to select "compound objects"

Little tip... model the curve AND the cross section in the TOP view.  :thumbsup:
The trouble with having an open mind, of course, is that people will insist on coming along and trying to put things in it

nathkel

Truly a HINT! I'll look at it when i get home.

Anyone else explored the problem?

jmyers2043

Cal gives good advice. Gmax -> Help -> word search for loft. 



There is also some discussion here

http://sc4devotion.com/forums/index.php?topic=8749.msg272334#msg272334

I've only used Loft when tinkering or experimenting. I never found a bat where it was needed.


- Jim


Jim Myers  (5th member of SC4 Devotion)

nathkel

Played around with it, and it got me oh so close. You build a path (in this case an arc), create a primitive or spline shape, then use the Loft Complex Object. Select the Shape you want curved, click on Get Path, then click the arc path, and it builds a mesh with the shape constructed along the path like a spine.

My problem was, in order to slope the shape up along the arc, i had to Select and Rotate the arc along the Z axis; this moved the XY points out of alignment of the grid (naturally -- it doesn't "auto lengthen" the arc to keep the same XY coords). Not only that, when you use the Get Path, the shape is banked, so that by the time the shape has traversed to the top of the slope, it's tilted by the same angle as the Z rotation you performed on the arc path.

Anyone have any ideas? I'll do the math if anyone knows which equations i should use to retain the XY length...

callagrafx

You should be able to turn banking off... and making it rise up is simplicity itself... but don't use an arc.  Draw an L shaped line and then select the end point.  Move this vertically upwards (use front view to do this).  Then select the central vertex (at the point where it changes direction) and use the fillet tool to make it curved.  Do this in the top plane.  You will need to alter the bezier curve in both planes to get a smooth upward curve but it should do the trick.  Once you're happy with the curve, apply the loft.  Sorry for the vagueness, but I'm not on a PC at the mo and can't be more precise.... however I can't remember if all the functionality (fillet of vertices etc) is in gmax, as I've been using Max for so long.
The trouble with having an open mind, of course, is that people will insist on coming along and trying to put things in it

nathkel

Thanks for that help.

Now i've been alerted to a new problem. Transit models use 3DS models not BATs, and since Gmax does not create these model types, imay be using the wrong software. &mmm

Anyone have any idea on free software to create these 3d models? Or maybe some other workaround?

memo

I have successfully been using Blender to export as .3ds-files. Make sure to use the settings Forward: -Z, Up: Y (or maybe Forward: Z, Up: -Y, can't remember the right one).

Besides, I would suggest to have a look at existing transit models first in order to understand how they work and to avoid making them too detailed. You can import them into Blender the same way. It is very important to use as few polygons as possible.

nathkel

Good to know. I'm hoping someone will come out with a tutorial. I hate learning a new software for one single purpose/project, and Blender is not easy as GMax -- and Gmax didn't come easy to me.

memo

Fortunately, there are plenty of Blender video tutorials – and there are multiple purposes you can use your new skills for. Anyway, it's not that hard at all.
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