Creating sketch geometry by external equations

Greetings and happy new year!

I'm exploring the possibility to employ Inventor for the creation of the complex rule-driven surfaces. The principle behind that approach is that cross-sections upon which the surface rests consist of multiple arcs, radii and key points for which are calculated mathematically. It is possible to acquire coordinates for accurate representation of any cross-section from the equation.

So this is the question. Is it possible in Inventor to build sketch geometry automatically based on the externally calculated coordinates?

As an example, let's assume I need to build 50 cross-sections of the given surface. Each cross-section is made of two connected radii, and coordinates of centres and ends of them are available from the Excel spreadsheet. Therefore, theoretically those cross-sections are already defined. What is left is to build 50 sketches. Doing that manually is rather tedious and counter-productive! The best way to do the job is to make Inventor read the file and build sketches according to the calculated data automatically. Is it possible?

are you talking about lines, splines, arcs, combination of all? I know you can import points but having inventor automatically use those points for creation of various sketch elements is something i think will be much more difficult. It sounds like maybe a job for VBA. Hopefully someone has done this and can put you on the right path.

Most of the time, I believe, that's going to be arcs and nothing else. Splines are unlikely.

I also suspect it is a job for VBA, not for basic Inventor functionality. I'm not afraid.

I only need few initial hints and a good advice.

Probably JD Mather will have something to say?..

Where i would probably start is by starting a sketch, recording a macro and using the insert points from excel inside the sketch then draw lines between the points and stop recording the macro. The funny thing is this is fairly easy to do in autocad using a script since you manually enter the coordinates for points.

I may try this as well. But I like the thought about the VBA becasue I feel it's a good way to do the job. Not least because the calculations defining the shape can be made within the same VBA code. Any good tutorial regarding VBA in Inventor?

None that i know of. Ive done a small amount with VBA in solidworks and that is my limit. Hopefully someone else will chime in that actually has. How is your C++ programming?

My C++ programming is around zero. You mean that it is possible to utilize C++ for this task?

Hi Enfiel3D,

What you are describing is actually a parametric model that could be created by other software and imported into Inventor. Please see my post on designplaygrounds.com for more information.

There are two current options and one future option that you may want to consider.

1. Rhino Grasshopper - Inventor 2011 now imports Rhino files and older versions can use the Autodesk Labs download to add this functionality.

2. Bentley GenerativeComponents - will export DWG files that can be imported into Inventor.

3. Future option: DesignScript for AutoCAD - the resulting DWG files could be imported into Inventor.

I hope this helps. Thanks.

Mark

Hi! Thanks for the info. I am currently not looking into other software.

well VBA is virtual basic for applications. Aside from recording macros you do need a bit of programming to really accomplish anything from my experience with it. Maybe i was doing it wrong:)

I know what VBA is. I did some programming in the past (well, in the school), and I have an idea about what it's all about. I'm sure I am capable of writing a program doing what I need if I find info how to make it build Inventor sketch geometry - if that is possible at all.

Hi! Thanks for the info. I am currently not looking into other software.

Hi Enfiel3D,

I've written both VBA macros and vb.net applications which generate geometry in Inventor as you described.

If you have some VB experience, it should take between 20 to 40 hours to write.

I can't send you any code I've produced at this moment, but if you post your own code, I will be more than happy to help out.

Have you posted on the autodesk discussion groups for inventor customization?

The idea someone else suggested of using Grasshopper to generate the geometry and then open in Inventor is even easier to do, would probably take less than an hour. I'm assuming that you won't use Rhino because you don't own a license? Because if you do own a license, it's an obvious and common workflow.

Hi Santiago!

I'm currently looking into VBA, and I think I will be able to solve the problem.