Why Are My File Sizes So Big?

Hi Everyone,

Just to give everyone some background info, I'm using AECOsim, a product of Bentley built on Microstation but I'm running the 'Microstation' option, so it functions essentially the same as Microstation V8i Select Series 4.

I've had extensive experience with Microstation XM but only just recently starting using this new program. Problem I'm having is I just recently started creating a scaffolding part cell library however when I create scaffolding bays out of it, my files are absolutely huge.

I've got a 116mb file which has about 10 scaffolding bays of probably 20 metres in height, when I publish this file to an i model, the file size drops dramatically to 1.9mb. Now I'm wondering why the original file size is so huge, and not closer to 1.9mb as I believe it should be.

Secondly, I built a gantry scaffold system and the file size was 29mb. I referenced this file into a new file, merged it into the document, deleted just a few insignificant items and then actually added more parts to it. The resulting file size was 741 kb which just doesn't make sense to me. 741kb is where i'd expect the file size to be at, but why is the original file that I merged it from 29MB? I'll try to upload this documents in my next post.

Surely there's something going on here that's making my file sizes so big, but I'm not sure where to start to identify it. If anyone can help then that'd be very much appreciated.

  • Are you interested in decreasing the sizes of these files or are you simply curious as to why these files are so large? If you want to "fix" the files, I can recommend a couple options described here: communities.bentley.com/.../117573, including compression and data cleanup. I must warn that these options may not be applicable and also that these options can only go so far.

    If you just want to know what's going on, the answer is probably specific to your problem and we would need the files.

    Cheers,

    Erik M.

  • Hi Tyson,

    to analyse what is happening with your design file in detail, to know both the design file itself and what tools and settings do you use would be helpful.

    Unknown said:
    Problem I'm having is I just recently started creating a scaffolding part cell library however when I create scaffolding bays out of it, my files are absolutely huge.

    Is it possible to share an example to better understand how your model, using what elements, is created?

    In my opinion there are several common reasons why a design file can be huge:

    • Not used objects (levels, shared cells definitions...) that can be cleaned using File Compress command. I don't think it's you case, but even though I recommend to try to switch on all compress option and use it (better on copy of your file :-) and to check if the size will change.
    • SmartSolids and Feature/parametric solids: In MicroStation V8i these objects are pretty complex structures implemented using cells. It means visually simple piece of 3D object can occupy large amount of space in DGN file. Andif copied many times, the size can grow quickly.
    • Dynamic views: If cached hidden lines visualization is used in e.g. sheets, the data are stored inside design file, which increase the file also. And in the case of complex models this cache can be huge.

    Unknown said:
    I've got a 116mb file which has about 10 scaffolding bays of probably 20 metres in height, when I publish this file to an i model, the file size drops dramatically to 1.9mb.

    Regardless "desktop i-model" (.i.dgn) is based on DGN V8 specification, data are stored in very different (optimized) structure. Because i-model is always read only, data holding brep structure and parameters are removed, so 3D solids are substantially smaller. Also anything not required for static display is removed.

    Unknown said:
    but I'm not sure where to start to identify it.

    In my opinon the best start would be to share an example.

    I recommend to check how your cell are big: Create individual files from every used cell, use full compress and check the size. Count how many times every cell is used to obtain a (very rough) expectation how the file should be big.

    It also would be interesting to try the same modeling task in MicroStation CONNECT Edition, because 3D solids are implemented in a very different way using different Parasolid technology. Because of this enhancements, in many situations visually the same 3D objects in CE are only a fraction of size if the same objects are created in V8i.

    With regards,

      Jan

  • Test 3.dgn

    Hi Guys,

    Thanks for the responses. Sorry for the slow reply, I have been busy with work and additionally slowed by the fact that I can't really use Microstation at the moment.

    It doesn't seem to be a compression issue. I just attached a file then - hopefully it works, to give a demonstration of how big my file sizes are.

    Thanks Jan for the informative post, that was a lot of helpful information. My components do all come up as smartsolid's, so maybe they are needlessly large but I don't know how to reduce the size.

    I have a file similar to the one attached but it's only 700kb - no idea why it's so small. However interaction with it in the model is still very slow. Like when I select everything, it takes a while to select and move etc. Additionally it takes a very long time to do a Cached Hidden Line reference. Will reducing the fill size speed up the time to change from dynamic to cached?

    Thanks heaps,

    Tyson

  • Hi Tyson,

    Unknown said:
    to give a demonstration of how big my file sizes are

    I played a bit with your file (but for a limited time)  and it seems  the reason of the size (and also of its slowness) is the complexity of elements. I checked the structure and everything is done from cells, they consitst from Smart Solids (which are again cells) with again Smart Solids inside (nested structure) and they are created from tens (hundreds?) of primitive elements including B-splines. It's probably not easy and fast to read and interpret such structure.

    It seems that e.g. STANDARD 2000 cell is 143 kB big and there are 20 of instances. So it means only this part of this model is about 2,5 MB big.

    Unknown said:
    My components do all come up as smartsolid's, so maybe they are needlessly large but I don't know how to reduce the size.

    I don't know if it's possible and what is the best way how to simplify your model. For sure it also depends on how you want to use the model. The complex Smart Solids structure is used to store information about the solid structure and to allow modifications. A conversion / transformation often removes this information.

    Unknown said:
    I have a file similar to the one attached but it's only 700kb - no idea why it's so small.

    It seems to be too small. Even i-model has about 1,3 MB.

    Unknown said:
    Like when I select everything, it takes a while to select and move etc.

    Unfortunately I have no advice here. But maybe somebody with more exprience with 3D modling will provide some insight what can be done.

    Unknown said:
    Additionally it takes a very long time to do a Cached Hidden Line reference. Will reducing the fill size speed up the time to change from dynamic to cached?

    Yes, because the model is quite complex. The file reduction may help, but I guess the main problem is in it's complexity (nested objects with many elements inside). To speed up manipulation in sheets you can try to use Cached Hidden Line: It requires extra time at the beginning to do necessary calculation, but because the result is stored inside DGN file, after it's finished everything is quite fast.

    With regards,

     Jan

  • HI Jan,

    Thanks a lot for the feedback and taking the time to look at my design file, it's really helpful.

    As to how I built each of those 3D components, the standard 2000 for example:

    Drew a circle, extruded it to the height, cut it with another circle to create the thickness I desired.
    For the stars on the standard, I draw the outline of the shape in plan view, turned those lines into a complex shape so I could extrude that down.
    I then copied that around the standard as many times as necessary.
    After doing all this, I used the 'construct solid' tool to make all of it one item.
    I then added just a dot under the standard stars so I can piece things together easier.

    After all of this, I turned the whole thing into a cell.

    Theoretically, I should never have to modify any of these components. All these items are just store bought and can't be changed, therefore I don't actually need any information that allows me to manipulate these items.

    Is there a better way I should have designed the 3D components or is there something I can do to just make it a dumb shape with no smart intelligence and less complexity attached to reduce the size down and allow for it to be processed better?

    Thanks,

    Tyson