I need to import a mathematically derived surface which (fortunately) can be defined by skinning over a series of about 100 circles. So I tried using the macro file format, which does allow lines in 3D to be imported, but so far I can only specify circles that lay parallel to the XY plane.

I need some way to specify circle locations in 3D- that is, the center location x,y,z, the diameter and the tilt angles (or a local workplane).

Can't locate much documentation on ViaCad's version of a macro text language. I've created a number of test shapes in viacad, exported to macro, renamed the file format to .txt, and read. But all tilted circles are exported as flat.

Any help or alternatives would be greatly appreciated.

No, I hadn't tried this approach. Surfaced-circles are convenient to tweak inside ViaCad, but I might be able to use the law spline functions- will investigate.

Thanks for the suggestion.

Just what I was looking for, thanks.

One other question- I kind of like the .spl file import as well. Is there a way to specify a variable in the .spl file? Currently, I save the equation I'm using to generate the 3D surface in a word doc, and search/replace variable names with numbers, then save as .spl. OK solution, but awkward.

Appreciate the help, for what I know is a quirky use of the program.

No problem- the macro or spl files are workable solutions for now. Normally I can design fully within ViaCad, but this project required surface positioning that is hard to achieve by modifying basic solids and curves.

I was able to finish the project using the spline file format- thanks.

If anyone else wants to use splines to precisely define a surface according to a mathematical function, but needs to easily vary parameters in the equations, here is useful suggestion:

I wrote the equation in excel, and placed the variables in separate cells. By using the text concatenating functions, excel automatically assembles the equation, substituting the parameters in the right places in the equation, and formatting a cell with the .spl code. Just cut and past into a .txt file, rename as .spl and import into ViaCad. Pretty fast and efficient.