MoI discussion forum
MoI discussion forum

Full Version: huge difference between file formats stp and MOI's 3dm

From: brr
27 Feb   [#1]
Hello Michael and forum community,

I work with a lot of STP files, which I then clean up by deleting invisible objects and inner parts before saving them in MOI's native format.

Usually, the cleaned version saved as a 3DM file in MOI is about twice the size of the original STP.
However, some files turn out to be extraordinarily larger.

For example:

original file with a lot of inner parts and surfaces: 72mb in stp file format
moi clean version is 875mb in 3dm file format.

another example:
88mb in stp file format
527mb in 3dm file format

From my side, I only noticed that this issue occurs with files containing highly detailed geometry, like this part. Please take a look at the screenshot.

My question is very simple: why does this happen, and what can be done about it?

Thanks in advance

Image Attachments:
MoI_GLQB5oDd3s.jpg 


From: Michael Gibson
27 Feb   [#2] In reply to [#1]
Hi brr, it's kind of hard to diagnose without being able to analyze the actual files, but
it's likely that the ones with the biggest difference are using instancing in the STEP file.
Since MOI does not yet have an instancing mechanism, when it reads in the STEP file
any instances will become a full separate object.

There isn't really anything to do about it currently.

- Michael
From: brr
6 Mar   [#3] In reply to [#2]
Hello Michael,

Thank you for the information. Are there any plans to implement instancing in MOI v5?

Thanks in advance.
From: Michael Gibson
6 Mar   [#4] In reply to [#3]
Hi brr, sorry no not likely in the v5 timeframe.

- Michael
From: Frenchy Pilou (PILOU)
6 Mar   [#5]
What is instancing ?
From: Michael Gibson
6 Mar   [#6] In reply to [#5]
Hi Pilou, instancing is a method of managing a large number of copies of the same object.

- Michael
From: Frenchy Pilou (PILOU)
6 Mar   [#7] In reply to [#6]
OK before an hypothetic instancing ...we can't simulate that ?
with copy to point by you
& VClone by MaxSMirnov

Vclone replaces the vector with the object with size and orientation!




From: Michael Gibson
6 Mar   [#8] In reply to [#7]
Hi Pilou,

re:
> OK before an hypothetic instancing ...we can't simulate that ?
> with copy to point by you
> & VClone by MaxSMirnov

Hi Pilou, yes you can simulate some aspects but the main thing that the simulation is missing is efficency in data size.

With instancing each "instance" is handled by maintaining the insertion point and not making a full separate object copy.

- Michael
From: Frenchy Pilou (PILOU)
6 Mar   [#9] In reply to [#8]
ok!