Import one scene into another - scale goes awry...

[jhiker]

I just don't get this and I never have...
I have two scenes, both have scene units set to mm. The scale of the objects is set to 1.
Individually the scenes look OK.
If I open one of the scenes and import the other one into it the scales are greatly mismatched. Why should that happen?
In this picture the tallest object in the scene inside the red box is about 350mm high. In the imported scene the grey enclosure is also about 350mm tall.
I have always had a problem with this and I just don't know why it happens. It's driving me mad!
Any thoughts?

[designgestalt]

I´d be curious on the answer here as I have that all the time ... !!

designgestalt

[jhiker]

I should add that both scenes were modelled in the same CAD system with units set to mm.

[jhiker]

Is this an issue for a lot of us or is it something just me and a couple of others are experiencing?

[Finema]

Hi
I can't reproduce that. Have you a simple file to test it ?

[KeyShot]

Which format are you importing? If you check 'keep scale' in the import dialog then the scale of the geometry in the imported file will be respected.

[jhiker]

I am importing one BIP file into another BIP file.
I don't see 'keep scale' in the import dialogue.
Thanks.

[Niko Planke]

Hey  jhiker,

To get to the bottom of this I think its best to get example files for us to investigate the issue.
The bip import should use the units set in the specific .bip file via "Edit->Set scene units".

If the units are set  in both files and you still experience the issue you can send the files securely via our https://keyshot.wetransfer.com/ for me to have a look. Send to niko-at-luxion-dot-com.

[jhiker]

Thank you Niko. In both scenes the units are set to the same - mm.
I'll send the files for you to investigate.

[theAVator]

Is the scale in your BIPs the same (not units, but scale, as seen down in the Position tab)? i.e. X=1, Y=1, Z=1, global 1.  Maybe not the correct answer, but something to check anyways. If one of those got wonky and then tried importing it into a different scale, then it just makes things more wonky. And if both got wonky before combining, then you've got one heck of a wonky donkey going on.

That tab has always eluded me from trying to make sense of it.

[designgestalt]

I can add from my side:
I have this all the time, also when combining bip files, so I can second, what jhiker is saying.

I create 95% of my data in Alias designstudio, I also pass all data I recive from clients through Alias, where I first prepare the files so that they are easier to handle in KS (i.e. applying different shaders to easier apply materials in KS, sorting the parts by layers etc.) so all my files are in the end more or less native .wire files (unstiched, NURBS data, although I very seldom enable the NURBS import in KS), which works very well.
the only issue is the scaling issue and this happens all the time. all parts come with the same scale from alias, all parts are positioned to the same coordinate system, all parts have the same unit settings!
the scale is always off by a power of ten (does that translate? I had to look that up in Google...), so it is no issue in between inches and cm.
I shall add, that this is not replied quickly here, I have spent many hours in trying different settings over the years and finally accepted it as a flaw, but I would pretty much rule a problem with the standard settings.

regards
designgestalt

[Niko Planke]

Hey jhiker,

I do not seem to be able to find the files in my inbox, did you send them already?

@designgestalt

That is defiantly something we should investigate. Just for me to make sure i am checking the right thing.  What version of Alias are you using?
And if you go to "Preferences->Construction options->Units->Linear" what are those set to?  This sound more like a cm vs mm issue.

[jhiker]

Hi Niko,
I just sent them again.
I'm using Alibre latest version, and Keyshot Pro.
Thanks.

[Niko Planke]

Hey  jhiker,

I checked the files from what i can see everything behaves as expected.

I suggest you check the scale of the file containing the gauges as far as i can see in the file, they are scaled to only be 2,3 mm high instead of the expected 350mm.

In case you struggle to find the scale in KeyShot here is how you do.
In the Scenetree select the part or group you want to know the extends of.
Then below the scene tree go to "Properties"
The Values noted as "Size:" are the size of the selected parts bounding box using the current scene unit.

When importing some file formats KeyShot will not be able to see from the file what unit is used in the CAD software.
You therefor need to be sure that the right unit is chosen in the import Dialogs "geometry" settings. This should match the unit used in your CAD software.

If you do not see the "unit" dropdown KeyShot is able to detect the unit used from the file format.

Depending what File format you use that might be the reason for incorrect scaling.

@designgestalt that also applies to .wire files. I suggest the next time you experience this you check the bounding box size in KeyShot for a part you know the scale for to verify the individual KeyShot files are scaled correctly.

My suspicion would be that one of the alias files was modeled in cm and the other in mm.

Let me know if this does not explain the behavior you see.

[designgestalt]

hello Niko,
thanks for going so deeply into detail here !!
there is one specific file that I keep carrying through for at least 5 years now. It is for one specific customer, where I only add to an old collection with some carry-over models. Also a lot of probs I can keep from the old file.
This is always giving me the trouble.

My thought was, that even though passing all the files through Alias it could be that the model in itself still keeps the history from the original CAD file. I sometimes also import files from Alias, that come in 90degrees rotated, although they where orientated correctly in Alias.

I am currently stuck in another project and cannot investigate any deeper timewise, but have to take a look into this project in 1-2 weeks for next years collection! I will check your suggestions and will let you know!!

thanks a bunch so far ...
this was already bucking me for years now and costed a lot of nerves and time, would be great if I finally could solve this!

cheers
designgestalt