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View Full Version : Native Inventor file vs STEP file tessellation



haknslash
08-22-2012, 08:54 PM
Wow I started working on some models today and noticed some strange issues when using my native Inventor files. The quality of these files is much worse than a STEP file. Anyone else notice this or have a reason why?

I created this model in Inventor and imported it into Bunkspeed. Looked rough no matter how much I changed the tessellation quality.

I then exported that file as a STEP (214 Automotive protocol) file from Inventor and then imported the file into Bunkspeed. Quality is much better.

I then did a test in Bunkspeed importing both file types using the default tessellation quality. Look at the results below....

jlowap
08-23-2012, 12:10 PM
Same here! just tried it...

haknslash
09-05-2012, 01:49 PM
So no comment from BS on this?

Ventare
09-05-2012, 05:57 PM
When I get a chance I'll look at the import pipeline to see what could be up. I'm not familiar with the specifics of how we import each file type (there are a lot, after all), so I can't make a good guess to a cause without some time researching. Usually if upping the tesselation slider doesn't help, that means that we're importing polygonal data directly; sometimes this means you can up the tesselation in the source file and it will improve the import. This is mere guesswork from me at the moment though.

I can take a look, but it'll be a few days at least before I can get to it.

Thanks :)

haknslash
09-06-2012, 03:12 PM
Thanks for looking into it Nick. I have played with adjusting the tessellation but it has not affect on the quality, even if maxxed out. I can email you a quick drill bit I made in Inventor if you want to test it.

As you can see in the screen shot it's still not smooth and this was with tessellation slider maxxed.

Ventare
09-06-2012, 10:33 PM
It's most likely not our tesselator handling the tesselation then. I'm not the import expert here, but I'd check for tesselation settings in the modelling app.

Best of luck. :)

haknslash
10-29-2012, 12:58 PM
It's most likely not our tesselator handling the tesselation then. I'm not the import expert here, but I'd check for tesselation settings in the modelling app.

Best of luck. :)

Hi Nick,

Inventor is a solid modeler so there aren't really any tessellation settings to adjust. AFAIK only the OpenGL smoothing in the Options configuration adjusts how smooth or rough models appear in Inventor, but it's purely graphical and has no bearing on the quality of the curvature of the physical solid model.

When you export out as a STEP file in Inventor you can specify which protocol and a tolerance but that's it as far as settings go. The issue isn't necessarily with the STEP files as they look great in Bunkspeed, it's that it doesn't translate the same quality with an Inventor file. It's not really an issue for me as I always use STEP files in Bunkspeed but just letting you guys know it does treat them differently.

Another issue regarding Inventor files is that Bunkspeed will sometimes bring over unwanted surfaces in the translation. This only seems to happen if you use a coil or sweep feature in Inventor and depending on how you used it and if surfaces were involved. For instance if you use Routed Systems and create hoses or cables, often times Bunkspeed will create a duplicate surface on top of the Routed Systems path (which is nothing more than a sweep feature using a surface).

I emailed David some sample files for you guys to play with and see what I'm talking about.

Thanks,
Kenny

david.randle
10-29-2012, 06:27 PM
Hi All - I apologize that i missed this thread. We have been provided test files and will submit the issues to our importer supplier for evaluation.

Thanks

david.randle
10-31-2012, 05:52 PM
Our resource has passed the following information on to me:

"The inventor importer extracts the current tessellation saved in the inventor file, so if you save a low polygonal representation the model will not be good for rendering.
We added a tessellation factor that you can control, this will be included in the next update coming soon."

The attached image shows the improvement in quality you control the tessellation for on of the models you sent.

320

haknslash
11-01-2012, 05:08 AM
David,

How are they saving native Inventor files with different resolutions of faces? AFAIK there is no setting for such. There only file I'm aware that Inventor allows you to manipulate facet resolution is when exporting to STL for 3D printing. I have used Inventor for many years but its possible there is some setting I'm unaware of but to be honest I've never heard of such.

Kenny

jlowap
11-01-2012, 11:09 AM
You cant... I've been using Inventor for years.


David,

How are they saving native Inventor files with different resolutions of faces?

Kenny

david.randle
11-01-2012, 05:43 PM
I'm not an inventor user so i am not sure. That's just the info they passed to me. I will ask them however. Regardless, the updated version will have a tessellation slider so you shouldn't have to worry about that in the future.

jlowap
11-02-2012, 09:01 AM
:D Thanks for all your help David!

Nice to see our comments are being listened too and your software guys are 'fixing' these things quickly :)

haknslash
11-06-2012, 01:32 PM
You cant... I've been using Inventor for years.

LOL I know. That's why I was asking as it isn't possible. Solid modelers are not like nurbs or surface modelers so I'm guessing they think they are the same ;)

Thanks David for the help! This will potentially save from having to create duplicate models as STEP files.

Cinny
03-19-2013, 12:40 PM
I'm sort of having the same issues . . . Did you change the tessellation settings when importing it or did you change them in Inventor?

david.randle
03-21-2013, 09:30 PM
Cinny - as long as you have 2012.6, you should be able to control the tessellation with the tessellation slider during import into our software. From the thread above, it doesn't appear that you can change the tessellation quality directly in Inventor.

Thanks

maryyou
09-10-2013, 10:45 AM
So no comment from BS on Aion Kinah (http://www.aionkinahkaufen.com/) this?