STEP file, which viewer?

No, Windows. I just don't see the point why things like a layout have to be sent in yet another new "standard" file format when the old ones worked very well. So I asked for the old ones. Which needs to be available anyhow to make boards.

Maybe it's just one more of those designed-by-committee file formats like ODF that never really goes anywhere in market share.

Thanks, Paul. Maybe I'll do that some day. But not right now where I even have to work the weekend instead of going mountain biking. Life is too short for spending too much time with new file formats that the world doesn't really need.

What I see lately is MEs that want to assemble an entire instrument in SolidWorks (or something even more expensive) so they need a STEP file of our board... every hole, part, connector, heat sink all 3D modeled.

Can you easily put a board layout into a STEP file?

And why do they need a STEP file? Whenever one of my clients did an entire instrument in SolidWorks they used the Solidworks file format (*.sldxxx, I think).

We use an older version of PADS. What we do (when we have to) is have PADS dump a 2D DXF file, import that into SolidWorks, add the 3rd dimension, and export as SLDASM or STEP. If we're lucky, we can get models of connectors and heatsinks from the manufacturers, and not have to make them ourselves. Most parts, like r's and c's and ICs, we just expand to simple bricks, enough to check for interferances.

Some people use the higher-end 3D cad stuff, $50K per seat instead of the $5K for Solidworks. They ask us for STEP files. The STEP files are verbose ASCII, and can be 10s of megabytes. They zip down nicely for emailing.

They get very close when it comes to model versus the real thing:

Same here, over 30MB. But when checking a design I prefer to have the very files that will be sent to the PCB fab house. Seen too much grief in the past, like when a conversion was done and all the high-power vias defaulted back to thermal reliefs.

I hate hierarchical schematics!

Sometimes we add copper patches to make sure we have flood-overs.

I *love* 'em (but it's rare to see software that properly supports them). I hate copy-n-paste. Too easy to make a mistake somewhere down the path.

You have to create (my preference) or find a 3D model for every important component, once, preferably when you make the footprint, and then it's as easy as any other board layout. Plunk it down and the model appears.

It's great when you want to look for interference with irregular molded or extruded structures, or (going the other way) create a board outline that fits within an irregular custom injection molding for a volume prodcut. I use it all the time for all but the very simplest of designs.

As a bonus, you can use it for high-quality documentation. The rendering is derived directly from the file used to create the PCB.

Step files are a lingua franca.. every CAD program of note can import them. Kind of the Esperanto of the MCAD world. IGES is another option.

The other files retain the 'tree' structure of the original parametric modelling but you can't even open them in older versions of the *same* software let alone in a competing program. That's right.. SolidWorks

Best regards, Spehro Pefhany

Actually I think it and IGES have almost all the share for what they do (MCAD interchange format).

Here's what McMaster offers in the way of 3D models for one product

In Altium, it's about four clicks. Includes whatever models you may have in the layout already (Altium can link or import STEP and such).

Tim

Many projects can't be done any other way. Imagine a medical high-end ultrasound system. 8-10 cards, each the size of a family pizza but square. Some of those have sections that repeat 64, 128 or 256 time. In a flat sheet structure that would be a hopeless mess.

Then the PCB house "corrects" them because they look out of place. I rather review the final stuff that goes out for fab.

For me that would be a pain because I deal with custom parts and odd new form factors all the time. But I don't do layouts anyhow, other than prescribing the really critical stuff.

Yeah, but Esperanto (predictably) fizzled. If even eDrawings can't read STEP then it must not have been all that successful in the marketplace.

That's the age-old trick to force people to fork over the maintenance fees and buy upgrades. I do not play this game. My mech CAD is at least five years old and all I use it for is to look at DXF files. That's the de facto standard. My schematic CAD is around 10 years old and works just fine. I will upgrade some day but only if they improve some major item on the wish list such as the missing hierarchy.

I have about a dozen active clients at most times and never seen it being used. Except now at a contract manufacturer.

Hmm, maybe it's coming, some day. With the major brands such as TE Connectivity it's PDF even at Digikey.

So you would instantiate every transistor in a microprocessor?

D2751 is on sheet 182 and its cathode, now where does that go to, ah, to Q1395 on sheet 275. Now wait, it also goes to ...

If any PCB house changes the copper patterns from our Gerbers, we wouldn't pay for the boards.

I've only designed one uP in my career, and I did show every chip on the schematic.

That's precisely why hierarchy is *needed*. The comesfrom and goesta are easily found by the interfaces.