Why Are Fusion Dimensions 10X greater on imported .STL files?

[lorne01]

I tried out Fusion 360 this evening.  I found it odd that every .stl i imported had the dimensions wrong.  I verified with Sketchup, and sketch up has the dimensions right.  I have figured out that the dimensions are out by a factor of 10.  

Is there some setting or something that needs to be changed to get the proper dimensions?  

The picture attached is of a ruler that is verified in Sketchup to be 10mm (length of the green line, but in Fusion it is 97MM.  Does this mean all my prints will be 10X bigger than they should be and i will have to mentally adjust for the error?  

I would appreciate if you have any insight.  

[Cathy.Wang_Autodesk]

Thank you to report the problem!

It's a bug and I can reproduce it, too. It's 10X bigger than it was.

I will report the case into the internal issue tracking system and ask the development team to look into it.

Sorry about the inconvenience!

Thanks

[Cathy.Wang_Autodesk]

Thank you to report it again!

There is a workgroud to deal with your problem.:)

If you want to import the file in a correct Size, you can try to  use local "Insert mesh" function. Which is only in Direct modeling design environment.

   a. Create a new file

   b. Right Click root component, Select "Do not Capture Design history". Then you will be in the Direct modeling design environment

   (If you already in Direct modeling environmen, you don't need to do step a and step b.

   

  c.In Direct modeling, go to Insert -> Insert Mesh

   

  d. You can select the right unit to import the stl file.

      I guess, your stl file was using the unit Millimeter. You can try to use Millimeter to import the file.

      Our server is default useing Centimeter. The you file is changed 10X bigger than it was.

 e. If you want to use cloud to open the stl file (Not use the local stl file). It's better to save the stl file using the unit Centimeter, then you can open the file using cloud/Data Panel in right size. 🙂

Thanks

[deyop]

Here is a link to another posting that attempts to explain this unfortunate problem of getting OBJ and STL files inserted with the correct scale.

Both STL and OBJ files are "unitless" files.  This means there is nothing in the formats that allows the system that is reading them to recognize what units were used when the file was created.  In most systems the units of the current document are applied when the conversion to STL is made.  In some systems you can define the units you want applied.  This is not a new problem.

When the conversion of the STL or OBJ is made in the cloud into the Fusion (F3D) format we don't know what the correct units are to apply.  There is nothing in the file we can read to know that.  They are just number values that correspond to the vertex locations.

 

If the file was created using centimeters and a box that was 1.0 centimeters on each edge was created the STL file would only contain information that indicated the vertex positions were 1 unit but not 1 centimeter in XYZ locations.

When you open the F3D document the default units that have been set in your preference (Preferences - Default Units - Design) are applied to the STL file.  So if the original STL file contained a cube that was 1.0 cm on each edge and it is read into a document that has a units value of millimeters it will apply millemeters to the values.  The centimeter cube just became a millimeter cube, off by scaling value of 10.  This is an unfortunate result of not being able to inform the conversion software in the cloud what correct unit should be applied to the STL.  We would like to provide an option that would let you inform the cloud translator but that is not an easy task.

Of course you may not know what units were applied when you recieve the STL file in which case you may need to do some measurements and apply scaling.  This gets a little bit trickier when you get a file that was originally created in inches.  We are looking at providing an option in the Scale command that would automate this a bit.  Not in yet though.

However if you are working in a Direct Modeling document or create a Base Feature you can insert locally from your disc.  You will find this on the toolbar under Insert.  When you do the insertion you will be presented with a dialog that will allow you to set the units that the STL was saved in.  Then we apply the correct units to the values and the size should be correct.

I hope this helps explain why reading these formats can cause problems.

Thanks

[Anonymous]

And two years later, this is still not fixed...

[Phil.E]

@Anonymous

I'm sorry to hear you are having trouble with it.

I tested a calibration block from Thingiverse. 10 x 10 x 40 mm. When I insert it into Fusion, and Fusion is set to Inch, and I pick mm import units, I get the correct result. A block ~1.5 inches long.

Is this not working for you? Please let us know what is happening for you.

 

[Anonymous]

I am a brand new fusion 360 user and just experienced this same situation as stormychel, took some googleing but I finally found this thread and it looks like this bug does exist. I tried 3 different files (all STL) and each was 10x too big upon import.

[Phil.E]

@Anonymous Hi,

Welcome to the forum.

The scaling of STL is handled on two ends.

1. How the STL was saved, as in, what units was it created or saved in?

2. When imported to Fusion you can pick the matching units and the STL will be the expected size.

So I'm wondering if you tried different units when importing and if any of those units produce the results you expect?

If you can attach the files and let us know what units they are supposed to be in, and what size they are supposed to be, we can analyze it to find the bug.

(notice that the dialog has a drop down menu for picking units)

 

[PhilProcarioJr]

@Phil.E

I have tested this on hundreds of models both .stl and .obj and as long as you set the correct units it comes in correct.

[Anonymous]

Thanks for the reply! I can't test anything more right now but tonight when I make it home I'll get time to play with it.

[HughesTooling]

Uploads to the cloud are going to be scaled wrong unless the STL was saved in CM, a file saved in MM with be 10x too big.

The bigger part is an upload and the insert is the correct size.

Mark

[afs]

thanks !

upload to cloud the object , and next insert to design the object is 10x large .
but if open design and insert mesh and select stl file its in correct size.

save my day .....

regards
estima

[PhilProcarioJr]

@HughesTooling

Your right and this should be considered a bug. @innovatenate can you see about getting this logged and fixed?

I have never ran into this issue because it makes little sense for me to upload a .stl when I have 10x the control just bringing it into Fusion.

Doing the whole upload to the cloud seems so cumbersome for stuff like this.

[HughesTooling]

I seem to remember this is\was a problem with stp and iges files as well. It was requested that uploads to the data panel should use the units you have in your preferences rather than default to CM for unitless file types. Although for once it is consistent for people working in inches or mm, it wrong for both.

Mark

[Anonymous]

Hi,

Last time I also tried to export/download a stp file from a component in fusion 360, but the dimensions were set to cm instead of mm, so the it was scaled by 1:10. Did anyone else had this problem too?

Thanks in advance!

[HughesTooling]

---

@bartvervaet wrote:

Hi,

Last time I also tried to export/download a stp file from a component in fusion 360, but the dimensions were set to cm instead of mm, so the it was scaled by 1:10. Did anyone else had this problem too?

Thanks in advance!

---

Yes but the unit information is in the STP file, when I open in Rhino it tells me the file is in CM and asks if I want to scale to mm.

Mark

[Anonymous]

Ok thanks,

Is there a possibility that I can save it in mm and not in cm? There should be an option to save it in your chosen units, like it does in solidworks for example.

thx!

[Phil.E]

Hi,

I just tested this again.

You are correct, no matter the Fusion units, cm is assigned to the STEP export.

However, the size is always accurate despite the units. For now you will have to import STEP files using "source units" which will be CM, and then change the model units in the destination CAD package after it's open.

This is logged as a bug with Inventor as a comparison.

Thanks,

[Anonymous]

Ok thanks a lot for your reply and confirmation. I hope in the future it will be adapted as the STEP export will be useless when a downstream CAD or person is not able to adapt the units.

Thanks,

[Phil.E]

I don't think there are any CAD systems that do not let the customer pick units. And since the model is not scaled (it's the right size) this should not be a blocker for anyone. Please let us know if you find a case where you are blocked.

Thanks,