Elegant Bridge

[Finis]

The goal is to make a new bridge model and a beauty scene based on my December 2010 SMC entry. This is about the visual appeal of the bridge. It does not matter if it could really be built.

Here is the SMC picture which shows the style of the bridge.


Here is a new tower. The main part is a sweep. The cable is a cylinder and two rounded cylinders. The cable parts are grouped and the axis is at the top rounded cylinder so it can be rotated to fit the road. The rectangle is a place holder for a road.

[Finis]

I am trying to make a curved road using macro sweep. It probably won't have guard rails but I'm going to make a version with them to check if I want them. I need help from those of you who know macro sweep and spline arrays well.

What I want to do is make a path to use for sweeping the road and guard rail and for a spline array to place the towers and guard rail posts along it. They need to fit to each other well.

I'm having a lot of trouble making a path and adding it to the library. How is that done?

How can I macro sweep the guard rail so that it follows the edge of the road using the same path? Does the location of the axis of a 2D polygon (for sweeping) matter? If so I could move the axes together after arranging the polygons and they would follow the path with an offset?

I can't get anything reasonable to happen with the spline array tool unless I draw the path. Using one from the library seems impossible. How do I do that?

Any advice, especially about spline arrays and paths and the path library, appreciated.

[tahnoak]

Finis...
Forgive me if I missed what you are truly asking.

In regards to making a path and saving it.. I use the drawpanel tool to create the curve that I want. When you have made it you can just click on the "path library" and then right click within it and save the path that you created in the drawpanel in the library.

Using the path is relatively straight forward. Select the face that you want to sweep along the path and then go to the library and select the path. Then select the "macro/sweep" button and it will sweep that face along that path.

Is that what you were asking?

[RAYMAN]

remember that when you do a normal extrude the tool remembers both the path and scaling so when you choose a different shape and use the path exttrusion
it uses the same path that you used for extusion you can even save the path you used the normal extrusion for into the library......for further use in the path extrusion tool.....
Nurbs programs even go further as you can choose many profiles and 2 path extrusion curves....

[RAYMAN]

thats a very extreme case that you can make in a nurbs tool but you can make it in Truespace too if you use the normal extrude tool and change the basic profile whie you are extruding..... Truespace keeps every change including path and size inside its memory and you can save that into your path library...
The spline tool works this way in truespace you import your object or make it and select it then you go to the spline array tool and the3 object changes to an object wit a sphere inside and then you tap in topview point for point where you want your objects to follow.. its as simple as that....

[compPanda]

I love bridges - looking forward to see this!

[Finis]

Thanks Tahnoak and Rayman and Comppanda.

My post about the path and array troubles wasn't clear. Sorry about that. However, you did help me to understand the basic functions that I was not understanding and that was part of my trouble. Thanks.

This is all TS 7.6 model side. If I have too much trouble then I might do some things in TS 5.

What I really wanted, I see now, was to make something close to a Road Tool where I could make a path and then have a road, complete with guard rails and posts, follow the path. I could almost do that if macro sweeps and spline arrays would follow a path with an offset applied.

I have been experimenting with the spline array, curves, paths, and macro sweep. (Instead of doing real world things I need to do.) I think I will be able to do the road by combining the abilities of those tools. Particularly the curve making abilities of the spline array.

I have found that:
- Macro sweeps can use paths from the library.
- Macro sweeps start with the beginning of the path in the center of the selected face or 2D shape and can't be offset.
- Spline arrays can be used to create a variety of useful curves.
- Spline array curve tools can create parallel curves.
- Curves are not paths.
- I can replace the curve followed by a spline array.
- I cannot use paths from the library for spline arrays.
- Alignment of the first spline array object and a replacement curve may be important.
- Curves can be stored in the path library but they become paths and will not work with spline arrays.

I will try to use the spline array on an object that is a cross section of the road to make the base road curve. Then I will use a spline array ability to create a parallel curve for posts and the guard rail. I'll save the curves in the path library. That will give me curves for arrays and matching paths for sweeps. Then I will sweep 2D cross sections for road and rails and make an array of posts.

Another parallel curve could place the bridge towers.

With the posts and towers as arrays I could adjust the number of them for best aesthetic appeal.

Question: Can a path from the library be converted to a curve?

Here is a picture of a test with spline array curve abilities. The blue curve is parallel to the central curve. The central curve is a copy of the array curve and the blue one runs along the edge of the array. The blue one would be for posts and a path version of it for sweeping the rail. A path version of the central curve would sweep the road.

[RAYMAN]

Question: Can a path from the library be converted to a curve?

.

Not that I can remember a way to do it!
The problem is the above that Truespace is a poly modeler mainly and it only mimics the properties of a nurb- spline ..... modeler !
But it isnt ....so its not as easy as you might think it is.
But you can use a trick for that you can make your path inside Photoshop and export it from there and import it into Truespace you can then
ad it also to the library thats a way how you can do it.
Marcel even uses Moi 3d for making paths and curves for Truespace.....
of corse you can also use something like illustrator... basically anything that can store and make ai files.
Peter

[Finis]

I don't need to turn paths into curves, just wondered. Since curves become paths when put in the library I thought there might be a reverse.

More tests indicate this might work but since paths and curves aren't the same there might be difficulty making path based sweeps fit well with curve based arrays. Matching or fitting things is one purpose of trying this method.

I probably won't use guard rails on this project but I think this method could be useful for roads and similar things if it works.

[RAYMAN]

I don't need to turn paths into curves, just wondered. Since curves become paths when put in the library I thought there might be a reverse.

More tests indicate this might work but since paths and curves aren't the same there might be difficulty making path based sweeps fit well with curve based arrays. Matching or fitting things is one purpose of trying this method.

I probably won't use guard rails on this project but I think this method could be useful for roads and similar things if it works.

It doesnt work with the simple method. what you want to do is called reverse engeneering ......
I covered that in my Tspline thread a few days ago. its basically the way to go from outlines of a polygonal surface to splines.....
some programs like Maya can do that or the T spline plugin for both maya and Rhino but not Truespace. What one can do is always the other way round from a spline to a poly....
Yes like you said this can be usefull for lots of tasks including roads.....thats why i´m always talking about that technology.
A reason also why I´m using nurbs as my main modeling technology....
Peter