Converting stl to stp

[Anonymous]

My stl file is too large to convert to an stp file and I really need to convert it, what can I do? Can anyone help me with this conversion?

[HughesTooling]

Why do you need them converted? What you need the solid model for will determine how accurate the conversion needs to be.

Mark

[Anonymous]

For manufacturing.

[HughesTooling · Accepted solution]

Well most manufacturers will not wont to work on a STP file that's just a converted mesh, holes will not be round, hard to pick up datums etc., so you will probably need to remodel using solids. Have you got any screen shots of what you are working with? Use the Photo option to embed, don't attach pictures.

Mark

[Anonymous]

Thanks, that is what I will do.

[art_of_takumi]

I can convert cerebrovascular images to STL data relatively easily using medical image editing software. However, we believe that it is difficult to automatically measure various vessel diameters and angles using only STL data. Therefore, we thought it would be preferable to convert to 3D CAD data such as STEP.

[art_of_takumi]

Was I correct in thinking that instead of converting from STL to STEP, the STL data is first solidified and then converted to STEP?

[laughingcreek]

for the use you are describing, converting a stl to a step will be a step backwards, and won't provide you the abilities you want. in about 90% of use cases, attempting to convert a mesh file to a cad format such as a .stp is a dead end workflow.

[TheCADWhisperer]

@art_of_takumi 

Examine stl carefully.  What do you observe?

You should observe that there are no curves in stl. All straight lines and triangular planar surfaces.  No curves.

[art_of_takumi]

STL could be converted to a STEP file by solidifying it. We found that conversion to a paid organic mesh was necessary.
We also found that if the meshes were not merged after solidification, bugs would appear.
The steps are
(1) Modify the STL.
(2) Convert STL to solid
(3) Combine the meshes of the solidified ones.
(4) Make the combined solid STL information into 3DCAD data so that it can be output as a STEP file using the organic mesh mode.
I was able to solve the problem by using the above methods.
The only problem is that it takes a lot of time for solidification.
A 15 MB file can easily take 30 minutes, so a 5-10 MB file may be realistic.

[art_of_takumi]

I just did the modeling using the method you recommended, and in about 20 minutes the conversion from quad mesh to T-spline took place, saving me quite a bit of time.
I think it is a very effective method.
One problem is that the amount of information in the model increases considerably when converting to quad mesh. (I assume this is due to the splitting of the triangle into 3 quadrilaterals).
I have to ensure accuracy, and I think this increase in information is unavoidable. In any case, we were able to solve the problem successfully. Thank you very much.

[TrippyLighting]

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@art_of_takumi wrote:

...
One problem is that the amount of information in the model increases considerably when converting to quad mesh. (I assume this is due to the splitting of the triangle into 3 quadrilaterals).

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The increase of data is NOT a result of splitting triangles into quads. It is the result of converting a mesh into NURBS surfaces. Meshes are relatively simple mathematically..

A NURBS surface is a mathematically precise description of a surface, free of any resolution and requires more computational resources an data.  

Converting a mesh into a "smooth" T-Spline does not increase accuracy! It might create more visual fidelity, but that does not mean the the geometry is a more accurate representation of the scanned object.

[art_of_takumi]

Thank you for your comments.I now understand about the T-spline.I am still new to fusion 360 and do not know how to use the information converted to T-splines.I am still new to fusion 360 and do not know how to utilize the information converted to T-splines.My ultimate goal is to use the 3D CAD information automatically.to automatically calculate the length of blood vessels, length to bifurcation, and bifurcation angle using 3D CAD information.I would like to create an algorithm that automatically calculates and computes the length of blood vessels, the length to branching, and the branching angle using 3DCAD information.As a first step, I wanted to see if I could convert STL information of blood vessels into T-spline 3DCAD information.

[TrippyLighting]

That is a very, very challenging task, if you want to use CAD software. My gut feeling is that you likely have much better luck using software that works directly and procedurally with mesh data . I will send  you a direct massage!