How can I create a box from 8 points?

If you HAVE to do it the way you say, a LISP that creates the boxes for you could be devised.

It depends on what you know. This would be a fairly simple routine in LISP which I know. I can't speak to VBA.

Ian -

What a great question. So simple to ask. Not so simple to answer.

But yes, it can indeed be done. A couple of questions:

1) do you need to have 3D solids as the final product? I ask because the easy ways to create these -- EXTRUDE and LOFT -- only work with planar initial objects (like a top and bottom polygon pair, or opposite sides as in your example). It doesn't sound as if your data describes perfect prismatic cuboids.

2) would 3D faces be acceptable? With 2007 and below, these would stay faces, so you could make each set of faces a block or a group to keep them together. With 2008, you can create a solid from the faces.

3) another possibility is a polyface mesh: one object, stretchable. This could be constructed from points, or by converting a set of faces to a mesh.

4) do you have many solids defined in each input data file (like one per line), or one solid per file?

5) is the data order IDENTICAL, i.e., the points of one vertical face listed counterclockwise from the bottom left corner, the points of the second face listed the same way as seen from the same direction?

-Bill

Ian Kelly wrote:

Bill,

Sorry for the delay in getting back to you, and thanks for your answer. As to your questions:

1) I think I do need solids, as I want to do a spacial analysis in GIS, and apply textures in Studio MAX, so as far as I know I do need solids.

2) I am not sure if 3D faces would be enough, particularly for the GIS analysis. But I think that my university can get 2008 for me, so I guess

3D faces would work.

3) I dont think a mesh would work, because of the GIS analysis.

4) I have the data in an excel format, and would write a small basic program to convert the CSV to whatever AutoCAD command line accepts. I guess the best would be a string of XYZ points, always in the same order?

5) The points are in the same order in the CSV file, clockwise around bottom then clockwise around top. Each set consists of 8 points, no more, no less.

I appreciate your help!

Ian

Bill Gilliss wrote:

Ian -

I was *sure* I read that plain old AutoCAD 2008 would allow one to create a solid from a set of bounding surfaces, but now that I have it installed, I can't find anything like that. Both the 2007 and 2008 architectural add-ons, however, can do this via the AECMassElementConvert and ConvertTo3DSolids commands, so you could either use one of the architectural packages from the start, or create the surfaces in plain AutoCAD and then have someone with one of the architectural packages do all the conversions to solids at one time.

By the way, MAX only uses surfaces, so will convert AutoCAD solids to surfaces when it imports them. What does the GIS software actually require? What import capabilities does it have? (What does it *do*?)

-Bill

Ian Kelly wrote: ...

Ian -

Could you provide the first 10 rows or so of the Excel file? I'd need to know exactly how these are set up to be able to get the data from a CSV export file into AutoCAD.

Post it here or send it to me at bill at realerthanreal dot com