STL file 1:10 scale

[cfairfowl]

Hi, Please can anyone help. I'm trying to get two assemblies 3D printed, I have been told they need to be scaled down to 1:10 scale. How do I export an Inventor assembly to an STL file at 1:10 from Inventor. The printers should I believe be able to do this easily but I'm not having much luck.

Thanks in advance. 

[JDMather · Accepted solution]

What are you document units?

When you export to stl, what units did you select?

If this isn't a units issue and your reason to scale is to fit build platen, simply use Derive to scale assembly

or use 

Direct Edit to scale part bodies.

If you have trouble figuring out - can you Attach your file(s) here?

[bwang-tecoustics]

I think this depends on the unit set up of your program. To me, I'm using Inventor, I use 1:1 to export STL if I set the model's unit as cm.

[Anonymous]

This is pretty easy to do, use the direct edit tools to scale the model, then do the export.

I made you a video showing the steps: https://knowledge.autodesk.com/community/screencast/a5d05419-cda8-4cdf-bee4-bc898b632e53

[cfairfowl]

Hi, you can’t derive an assembly into an assembly only a part into a part.

The parts and and assembly are in mm.

Thanks.

[JDMather]

You can Derive to scale or you can Direct Edit to scale.

Your choice.

You never clarified - is the reason for need to scale because the stl is "wrong size" (units) or is it because you don't want 1:1 print, but scaled down from true size to accommodate printer envelop.  The solution will be easy once the problem is fully defined.

Also, will it be printed as one monolithic assembly, or each individual component.

[cfairfowl]

Thanks, I appreciate your help, I now know you can do this and have got it to work - brilliant, I did as directed, derived the assembly into a part using 0.1 scale, measured the assemblies and they are OK,
Saved as an STL file, I’m not sure how the printer will cope because there are some fine gaps and the real life tolerances are quite tight so I’m anticipating a 3D pile of junk.

I’ll let you know how I get on anyway.....

This is amazing, thanks chaps. Within a few hours of posting I got help and sorted it.

VERY much appreciated.

[Frederick_Law]

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@cfairfowl wrote:
there are some fine gaps and the real life tolerances are quite tight so I’m anticipating a 3D pile of junk

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???

Why would you scale it to 1:10 then?

You started with wrong unit?

Most 3D printer slicer take STL in mm.

What unit did you model in?

What unit the 3D printer use?

[johnsonshiue]

Hi! I suspect the unit you chose to export STL was incorrect. If you export Inventor part with internal unit (cm), the STL file will be 1/10 of if mm is chosen.

Inventor model is true scale. The geometry does not change size with respect to unit. Simply click Options button when you export to STL -> choose the correct export unit. Most 3D Printer uses mm.

Many thanks!

[cfairfowl]

Hi,

The parts and assembly is of a mechanical structural locking system for a subsea oil and gas structure. Its outer diameter is 840mm diameter and it’s 2000mm high. It’s in mm because in England we use the metric system, the detailed fabrication drawings are also in mm so the parts and assembly are 1:1 (real life size) in mm. The model needs to be 84mm in diameter so it can be hand held and viewed by clients in meetings. Trying to get the full sized model into meeting rooms may present a little difficulty and I don’t understand why I would want to change the working units? Converting it to Metres or inches would be of absolutely no help to me.

The printers say they need the STL files at the size to be printed. i.e. 1:10 because they can’t or won’t Scale it for me prior to printing. Anyway I have done there job for them. I derived the assembly into a part file 0.1 scale and saved it as an STL file. All they need to do now is press a button and charge us a fortune.

I guess an option for scaling the outputted STL file from Inventor would be a good feature to have, I could have saved it at 0.1 or 1:10 when creating the STL file.

Thanks for the reply.

[mcgyvr]

@cfairfowl  People were only asking about the units because often times we get questions of people who tried to 3d print something and when they opened it in the 3d printer software the part was 10x as big. That is due to them exporting the item in the wrong units. You can change the units during export so people just wanted to make sure that this wasn't just an "oops.. I selected the wrong export units" issue. You have now explained that you need to actually scale down a larger model for presentation purposes which is information that wasn't presented originally so now we know it wasn't just a units issue.. 

Deriving seems to have gotten you what you needed so please mark the post that suggested that as the solution to properly finish this post. 

[Frederick_Law]

Making scale down model involve more then just scale it down.

As you've pointed out, tolerance.

Whatever clearance you had, it became 1/10.  So most likely it won't fit.

Usually you'll need to modify fitting features int the scaled down model so it'll assembly correctly.

Probably that's why your 3D printing shop didn't want to scale it down because they know it won't fit together.

[cfairfowl]

Thanks, the printers have given us access to their virtual 3D print to interrogate, this may or may not show up any significant issues.

We’ll see.

Cheers

[cfairfowl]

Hi and thanks again for getting back to me. I did say I needed to “scale down” the assembly by 10 or 1:10th the original size. The reason I specifically didn’t mention “units” in my post is because it’s not a units based issue and that would have confused things. The reason I asked about scaling is I wasn’t sure if the specific 3D print software makes allowances and adjustments to account for printing tolerances when it scales the STL file down or up. I have a feeling my client who wants the 3D print made has a lot more faith in the accuracy of the 3D printing process than I do. I have suggested he has a small part printed to see what clearances are achievable, that way it will be cheaper and will take up less room in his waste basket. Unfortunately, units was mentioned by others in the post and that distracted others I believe. I was planning on closing the post after I see and inspect the 3D print and write a small report letting folk know how I got on with this (deriving) method of scaling and printing from it but I’ll do as you ask and close it now.

Thanks again.
Chris.

[cfairfowl]

Hi, This works for parts but if I open an assembly the direct edit scale feature isn’t available. I need the whole assembly to be scaled down. 

Cheers

[mcgyvr]

Any decent 3d printer software/slicer will also have the ability to do a uniform scale right in its own user interface.

[JDMather]

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@mcgyvr wrote:

Any decent 3d printer software/slicer will also have the ability to do a uniform scale right in its own user interface.

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My guess is the vendor has been burnt by scaling models in the past and insists the customer send them what the customer wants, and that way if it is the wrong size - well, it is the customer who sent them the wrong size.

It would take a lot of editing by the vendor to make clearance tolerances work before/after scaled down.

[cfairfowl]

Hi, you would have thought so but not all of them do.

Cheers

[Frederick_Law]

Let your client know, they cannot check fit with a scaled model.

Scaling down make 0.1 clearance to 0.01.

A lose fit become a tight fit.

[Frederick_Law]

I print smaller part so we can using it meeting.  Much easier then saying "need a hole over there".  Or try to explain complex shapes.