DesignCAD User Forum

General DesignCAD Topics => General Discussion => Topic started by: corlett on April 15, 2019, 04:43:21 AM

Title: .STEP Files
Post by: corlett on April 15, 2019, 04:43:21 AM

I don't engage with the forum often enough so while I am looking for a solution to my re-paint issue I would like to bang on again about .STEP files.
It's now 2019 is the import of .STEP files sill a back burner?
Am I the only one dealing with outside people working in this format?

We supply universities with scientific instruments and they all get academic cut price CAD systems so its all .STEP
As regular as clockwork we get a request to quote with an enclosed .STEP file. 
Q. "Clive can we open this drawing".  A "no!"
If this was a feature in the next version I would upgrade in a hart beat. Just import would do.


PS. Don't get me wrong I still love DCAD, you don't do 11800 drawing with a tool you hate.

Previous rants below.

I posted in 2013

Prl suggested that "IMSI has plenty to chew on at the moment with DesignCAD."

and again in 2014;topicseen#msg40965

Prl - Succinctly quashed my hopes with " I'm guessing the answer is still as it was in the other topic"

Title: Re: .STEP Files
Post by: Dr PR on April 15, 2019, 10:15:38 AM

I think the main problem with generating STEP files is that they are triangle based grids and DesignCAD was rectangle based.

Somewhere along the way DesignCAD's rectangular grids were redesigned so each rectangle was actually two right triangles. But STEP (and many other formats) use irregular triangles, so it isn't easy to convert a rectangular grid to an irregular grid.

However, "Solid Surfaces" were introduced to DesignCAD as a part of the RedSDK conversion (RedSDK worked with irregular triangle grids). I think, but I am not certain, that the Solid Surface grids are irregular triangular grids. As a consequence it has become possible for DesignCAD to generate irregular triangle format STL and SketchUp file output, and import SketchUP files.

So it should be possible to produce STEP output. However, as I recall, STEP is a proprietary (patented) file format and the owners want an arm and a leg to let you use it. So STEP may be prohibitively costly for DesignCAD.

Title: Re: .STEP Files
Post by: corlett on April 16, 2019, 02:26:40 AM
Hi Dr PR

Thanks for that.
If technically it can't be done then I will stop worrying about.

However my main problem is reading these files not generating them.  Therefore a follow up question would be; I can see that a propriety format would prevent writing but does it cover reading.

I have alternative idea. ( I am more than a little ignorant here so be gentle ) .STEP files are 3D in nature I think.
I produce a lot of 2D production drawings of machined components and only use 3D models to solve complex assembly/clash issues. I can think in 3D I don't need a computer to do it for me.

My immediate problem.
The .Step files are given to me for third party dimensional information, how I am to fit with existing equipment, etc. 
Academics consider themselves to be accomplished mechanical engineers because , well, how difficult can it be!  They put together a model on their academic licence ProEngineer and send it to me. There are so many ways to mess up a CAD file with poor drafting, bloated point count, for these reasons most downloaded models are unusable.

Actually it would be more useful to have 2D orthogonal projections of  3D .STEP files. Like the very useful DCAD SaveAs 2D Projection feature.
I could get the dimensions I need and over draw accurate scale drawings.

Well this reads a lot like me, me, me, as it's a solution to my problems; but it would allow the use of these ubiquitous .STEP files in a practical way.

Title: Re: .STEP Files
Post by: Dr PR on April 16, 2019, 12:13:16 PM

I have had similar problems over the years. Unfortunately, I can't give a certain work around for STEP files, but here is a suggestion. Look around for a STEP file viewer, especially one that can give you information or generate 2D views or slices. One way or another (print screen?) you may be able to get the information you need.


Years ago I was working with a company that had offices in the US and in Ireland. Everyone was using different CAD programs. A fellow in Ireland was designing a part and I was supposed to create a part that accepted it with a slip fit. However, no one here could open his files successfully (it turned out that he had accidentally turned on an encryption feature that scrambled the data). We were on a tight deadline!

I found a viewer program that would display his files, and it would generate 2D slices that could be saved in DXF format. So I made a lot of slices, imported them into DesignCAD and assembled them to get the dimensions of the part he was making. From that information I created my design and delivered finished machined parts just before the deadline.

The next day the fellow figured out the problem and sent the unencrypted file!