STEP file translation errors.

me_again

I've uploaded a .STEP file, but the result I see contains translation errors.

The file is originally produce by SpaceClaim in ACIS (.sab) format where it looks like this:


If I upload and view this is CadExchange it looks like this:


If I use CAD exchange to translate it to STEP format and then view it, it looks like this:


But when I import the .STEP file here and view it, it looks like this:

Note: Then convex edge of the flange has been mis-converted as a concave edge.

I suspect that explains a lot of the problems I have had down stream when using this site to import .step files.

Jake_Rosenfeld

Hi @me_again

Sorry you're having this trouble.  It would be helpful if you reported this to our support team using the "Report a bug" or "Feedback" button under the "?" menu in your Part Studio.

In the meantime, we accept ACIS .sat format, so maybe you could try saving your file out as that and then importing directly into Onshape?  Otherwise, if you only have access to the .sab file, you could use your exchanger to change it to Parasolid (.xt) rather than STEP, as we use Parasolid as our modeling kernel.

me_again

Jake_Rosenfeld said:

Hi @me_again

Sorry you're having this trouble.  It would be helpful if you reported this to our support team using the "Report a bug" or "Feedback" button under the "?" menu in your Part Studio.

In the meantime, we accept ACIS .sat format, so maybe you could try saving your file out as that and then importing directly into Onshape?  Otherwise, if you only have access to the .sab file, you could use your exchanger to change it to Parasolid (.xt) rather than STEP, as we use Parasolid as our modeling kernel.

Thanks for the response Jake.

I just converted the original .sab file to .sat using SpaceClaim's sabSatConverter.exe, and then uploaded here directly:

    https://cad.onshape.com/documents/c4d14e10da3f21c434d02bfe/w/37b93269860b2d4095bde767/e/ca84acb67d12088b756b588d

The result is a file labelled "translatable", but not translated? (I initiated an investigation as requested.)

Then I use CadExchanger to convert directly from .sab format to parasolid .x_t format, and then attempted to upload that.

The results was:
 

       Translation not supported b17xf144xe359.x_t failed to translate.
       The following 1 part(s) failed validation and have been removed:

• 1 unnamed - number of faults:1

        Created at 8:45 PM Today

Let me know if I can provide further information, or files, or if you have further suggestions?

Thanks.

Jake_Rosenfeld

Hi @me_again

Thanks for all the info.  Our internal team will investigate.

NeilCooke

@me_again if you try importing again with “allow faults” switched on, you will see the same result as shown in CadExchanger. Looks like there is a surface missing - Onshape will reject an import unless it is a fully enclosed solid.

NeilCooke

However, I exported it as STEP from CadExchanger and it came in just fine. Very strange.

me_again

Sorry, I've looked at so many different versions of this that I'm a little confused about which ones you are referring to in each of your replies?

@me_again if you try importing again with “allow faults” switched on, you will see the same result as shown in CadExchanger. Looks like there is a surface missing - Onshape will reject an import unless it is a fully enclosed solid.

To which version are you referring here? The .STEP version uploaded/translated okay (except for the concave edge).

It was the .sat and .x_t versions that didn't translate. Which of those had the missing surface when you allowed errors?

However, I exported it as STEP from CadExchanger and it came in just fine. Very strange.

By which you mean: the .STEP version didn't have the missing surface, (although it still had the concave edge where it should have a convex one)?

(Also, which version of CadExchanger is that you are using? The screen display is different to the cloud version I'm using.)

NeilCooke

I imported b17xf144xe359.sab.sat (the original) into the latest version of CadExchanger for Mac (never knew this program existed before) and the surface was missing. Export as STEP and it comes in as in the image above - I was so focused on the missing surface I missed the inverted arc, sorry. Importing the .x_t had the missing surface.

Do you have any other examples that exhibit strange behaviour?

NeilCooke

@me_again I just tried it again.

• CadExchanger for Mac, imported b17xf144xe359.sab.sat from your original Onshape doc (shows missing surface)
• Exported as sat
• Imported into Onshape - this time it's perfect
• Must be something to do with the original conversion, perhaps try it again from the sab file?

I also just tried the above with their web version with the same results

me_again

NeilCooke said:

I imported b17xf144xe359.sab.sat (the original) into the latest version of CadExchanger for Mac (never knew this program existed before) and the surface was missing. Export as STEP and it comes in as in the image above - I was so focused on the missing surface I missed the inverted arc, sorry. Importing the .x_t had the missing surface.

Do you have any other examples that exhibit strange behaviour?

Not to hand.

I have repeatedly had trouble with converting any .sab file produced by  SpaceClaim that contains thread forms; the problems manifest themselves down stream at SimScale when I try to mesh them for simulation purposes; the meshing fails with small triangle errors.

For the most part, I've re-drawn the parts from scratch and the new version work. (I don't have a satisfactory explanation for this!)

This flange nut is the first time where a visibly obvious defect has shown up in a conversion that OnShape accepted without errors.

I'm a bit stumped as to what to try next.

(I'd try re-creating the part here in OnShape, but I and your sketcher do not get along )

me_again

NeilCooke said:

@me_again I just tried it again.

• CadExchanger for Mac, imported b17xf144xe359.sab.sat from your original Onshape doc (shows missing surface)
• Exported as sat
• Imported into Onshape - this time it's perfect
• Must be something to do with the original conversion, perhaps try it again from the sab file?

I also just tried the above with their web version with the same results

Do I read this right. You import the .sat file, then export it again as .sat; and then upload the exported .sat to OnShape and it comes in correctly?

(If so, I'll try that

me_again

Update: Now I see why. They aren't listed because those components have imported as surfaces not solids!

You asked if I had any other parts with weirdness

NeilCooke said:

Do you mind if I ask you a follow-on question here? It relates to this https://cad.onshape.com/documents/9bfda64bffb9e12362dd3787/w/3028677bfab9eb655f4b7f70/e/f63c60ecf95ce303ca901eb8 where I have finally succeeded in uploading all 18 components of my assembly.

Having got them uploaded as individual parts and deleted all the extraneous tabs, I want to assemble them all together into one assembly.

However, when I select the 'Insert' tool, the 'insert parts and assemblies' dialog only offers me 16 of the 18 parts?

Specifically, parts 'b2xf26xe62.sab' & 'b18xf26xe56.sab' are missing from the dialog list?

(I'd raise a new ticket, but I don't see any mechanism for that? )

( I'd ask on the forums, but I have asked many questions there in the past, I whilst Jousef diligently responds with "I've referred this to @powers" etc; I've never yet received an answer there that solved my problem.)

Thanks for your time, M.

MBartlett21

me_again said:

NeilCooke said:

Do you mind if I ask you a follow-on question here? It relates to this https://cad.onshape.com/documents/9bfda64bffb9e12362dd3787/w/3028677bfab9eb655f4b7f70/e/f63c60ecf95ce303ca901eb8 where I have finally succeeded in uploading all 18 components of my assembly.

Having got them uploaded as individual parts and deleted all the extraneous tabs, I want to assemble them all together into one assembly.

However, when I select the 'Insert' tool, the 'insert parts and assemblies' dialog only offers me 16 of the 18 parts?

Specifically, parts 'b2xf26xe62.sab' & 'b18xf26xe56.sab' are missing from the dialog list?

(I'd raise a new ticket, but I don't see any mechanism for that? )

( I'd ask on the forums, but I have asked many questions there in the past, I whilst Jousef diligently responds with "I've referred this to @powers" etc; I've never yet received an answer there that solved my problem.)

Thanks for your time, M.

@me_again
For some reason, they have imported as surfaces. In the insert dialog, make sure surfaces is selected as well as parts

Jake_Rosenfeld

@me_again

In those two Part Studios you'll notice that some of the surfaces that are required to enclose the part are missing from the import.  Because of this, the imports come in as a set of surfaces rather than a solid part.  You can tell visually, but you can also tell because the bodies come into the Parts list under the "Surfaces" header rather than under the "Parts" header.  Here are some screenshots, I've tried to capture an angle which shows which surfaces are missing visually:



You actually can insert these surface bodies into your assembly as long as you have the "surfaces" filter selected in the insert dialog:



But most likely you'll want to actually fix the missing surfaces by following @NeilCooke 's steps.

owen_sparks

@me_again

It looks like there is an error in those two missing files.  They have missing faces, so they're not watertight.  As such they're shown as surfaces not solid parts, and can't be put into an assembly as a solid.

You can however click the "surface filter" in the assembly dialogue if you wish, and it will then be available.

Hope that helps,

Owen S.