topic Re: STL File scales to 25.4 times the original size in Inventor Forum

STL File scales to 25.4 times the original size

rgollob — Thu, 09 Aug 2018 18:40:03 GMT

I know I have dealt with this issue in the past and cant seem to remember how to fix the issue.

When I save the stock as STL from simulation in Inventor HSM (Units in inches) and then import it to create an ipt file it scale the imported file x25.4 as if it was exported as metric. I have browsed around the web and in the forum and cant seem to find the solution I stumbled on last time.

Re: STL File scales to 25.4 times the original size

johnsonshiue — Thu, 09 Aug 2018 18:48:24 GMT

Hi! I believe the STL was probably mm-based. You need to start a new mm template and then import the STL file there. You probably imported it to an inch-based file.

Many thanks!

Re: STL File scales to 25.4 times the original size

rgollob — Thu, 09 Aug 2018 19:03:09 GMT

what your saying is that you need to import as millimeter then go in and change the file units to inch?

Re: STL File scales to 25.4 times the original size

johnsonshiue — Thu, 09 Aug 2018 19:12:47 GMT

Hi! I think you misunderstood my reply. STL is unitless. But, the actual size depends on what document unit you exported from. For example, if you have a 1mmx1mmx1mm cube and you export it as STL (in mm), you will get mesh in 1x1x1 (unit free). Now, if you import it to an inch part file in Inventor, the mesh will become 1inx1inx1in, which is 25.4 times bigger than the original mm cube. Does it make sense? If you are still in doubt, please attach an example here. Forum experts should be able to guide you through the process.

Many thanks!

Re: STL File scales to 25.4 times the original size

TheCADWhisperer — Thu, 09 Aug 2018 20:09:29 GMT

@rgollob wrote:

I save the stock as STL from simulation in Inventor HSM (Units in inches) and then import it to create an ipt ....

This is a bit of a sidebar question - since I have no experience with Inventor HSM, but can you explain a bit about why you are saving as STL format? I can't imagine using that for anything other than 3D printing.

Just curious - please don't take offense.

Edit: Oh wait a minute, I missed the "from simulation" on the first reading.

When saving from HSM - is there an Save As Options something like this image?

Re: STL File scales to 25.4 times the original size

rgollob — Thu, 09 Aug 2018 20:55:39 GMT

@johnsonshiue wrote:
Hi! I think you misunderstood my reply. STL is unitless. But, the actual size depends on what document unit you exported from. For example, if you have a 1mmx1mmx1mm cube and you export it as STL (in mm), you will get mesh in 1x1x1 (unit free). Now, if you import it to an inch part file in Inventor, the mesh will become 1inx1inx1in, which is 25.4 times bigger than the original mm cube. Does it make sense? If you are still in doubt, please attach an example here. Forum experts should be able to guide you through the process.
Many thanks!

Thank you @johnsonshiue

I understand what your saying in this reply, but in my case I am creating an stl from a file that in inches and importing to a file that's in inches. it would seem that the stl file (though should be unit less) is in mm as it then imports and measures 114.3 inches and the measurement is the native file is exactly 4.5" (114.3/25.4=4.5")

I was able to solve this issue using exactly what I replied to you with. That is using options I was able to select units as mm for the import process, then went to tools - document setting - Units and changed it to "inch" now what was measuring 114.3inches was now measuring 114.3mm and once the units were changed back to inch is now measuring 4.5"

Re: STL File scales to 25.4 times the original size

rgollob — Thu, 09 Aug 2018 21:03:46 GMT

@TheCADWhisperer wrote:
@rgollob wrote:

I save the stock as STL from simulation in Inventor HSM (Units in inches) and then import it to create an ipt ....
This is a bit of a sidebar question - since I have no experience with Inventor HSM, but can you explain a bit about why you are saving as STL format? I can't imagine using that for anything other than 3D printing.
Just curious - please don't take offense.
Edit: Oh wait a minute, I missed the "from simulation" on the first reading.

When saving from HSM - is there an Save As Options something like this image?

@TheCADWhisperer

In my particular situation you can save the stl file and in your rest machining setting you choose from stl file. Which will allow for machining from that material condition and works significantly better that "from previous operations".

sometimes I also need to create a solid. and though I cant use the stl as a solid I can measure the surfaces created from importing the stl file.