How to scaleup a .step object in only one direction?

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amarilisppt
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Joined: Mon Apr 08, 2019 8:24 am

How to scaleup a .step object in only one direction?

Post by amarilisppt »

OK, here you are. I scanned (3D) an object and imported the .step file into FreeCad. Then, transformed it into a solid shape in order to be able to add other shapes, geometries, etc... within Freecad: works very well.
I now would like to give more thickness to this object, i.e. like an extrusion through the Oz axis. How to do?
I tried extrusion (although this is not a face), a sweep and an homothetic (Draft menu), but none gives the expected result.
Thanks. Photo again, as the FreeCad file is too large.
I scaleup through MeshScale (cf. photo before/after) but assume the center point is to be adjusted, but... how? I tried with a far away center point, but it leads to no modification.

Best regards
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MesScalex2OnzOnly.JPG
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openBrain
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Re: How to scaleup a .step object in only one direction?

Post by openBrain »

Please be clear about what exactly you want : scaling, offsetting, thickening, ... ??? This are really different operations, and tools.

Also be aware that you will necessary go into troubles with such "meshed" objects that have thousands if not millions of faces.

Also what purpose of this thread compared to https://forum.freecadweb.org/viewtopic. ... 06#p540191 ? :?
amarilisppt
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Re: How to scaleup a .step object in only one direction?

Post by amarilisppt »

Hi,
thickening (in z), as written. One on the forum suggested to use Mesh-Scale, that is why I tried and give the feedback.
Yes, there many faces, as ths object results form a 3D-scan of a real object, because of its complexity and reliability of having such a structure.

The request is the same, but I was asked to put my post in the whole forum (not the French one only) with an English title.

Best regards
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thomas-neemann
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Re: How to scaleup a .step object in only one direction?

Post by thomas-neemann »

amarilisppt wrote: Fri Oct 15, 2021 1:58 pm

here is a possibility, but as already mentioned here it can take a long time with a mesh


https://www.youtube.com/watch?v=GpM3AMPXpDY

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Gruß Dipl.-Ing. (FH) Thomas Neemann

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mrdic
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Re: How to scaleup a .step object in only one direction?

Post by mrdic »

Autodesk's Meshmixer has specific functions to trim, shell (hollow) and offset face and vertex collctions easily. Even if you give them a CAD file attachment like .step, meshes aren't suited to many CAD processes. If you'd like to know how and why, https://www.npowersoftware.com/NewCybor ... rview.html
There's a free retopology tool called Instant Meshes that can convert a tri-dominant mesh to quad-dominant, which can make reverse engineering a CAD surface from a mesh easier.
heda
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Re: How to scaleup a .step object in only one direction?

Post by heda »

suppose pointcloud is not too large to attach...
TheMarkster
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Re: How to scaleup a .step object in only one direction?

Post by TheMarkster »

amarilisppt wrote: Fri Oct 15, 2021 1:58 pm OK, here you are. I scanned (3D) an object and imported the .step file into FreeCad. Then, transformed it into a solid shape in order to be able to add other shapes, geometries, etc... within Freecad: works very well.
I now would like to give more thickness to this object, i.e. like an extrusion through the Oz axis. How to do?
I tried extrusion (although this is not a face), a sweep and an homothetic (Draft menu), but none gives the expected result.
Thanks. Photo again, as the FreeCad file is too large.
I scaleup through MeshScale (cf. photo before/after) but assume the center point is to be adjusted, but... how? I tried with a far away center point, but it leads to no modification.

Best regards
The scan software generated a .step file or .stl file? The .step files I have worked with are all already solids, but perhaps there is a non-solid type I have not encountered.

OpenSCAD workbench can scale mesh objects in each direction independently, but I don't think this is what you are trying to achieve.
amarilisppt
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Re: How to scaleup a .step object in only one direction?

Post by amarilisppt »

Hi, thanks for your help.
It was a.step file, but the problem is not directely here. Now, it is a solid indeed, but I do not find the accurate function within FreeCad to make this object thicker. In fact, my question could be for any solid, except that, here, there are many many cells in the mesh.
It is not a shape, it is a solid. Thus,n the Extrude function is unefficient.
Best regards
heda
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Re: How to scaleup a .step object in only one direction?

Post by heda »

imho there is no command to thicken a mesh.
any face can be extruded, so hypothetically you can extrude every face, and then fill the voids created by the fact that the normals of the faces are not aligned.

i think you are barking down the wrong tree, before one thinks of putting meshes into fc, better prepare them...

why not just cut the mesh and translate "one side" for thickness and then fill the "hole" inbetween?
fc could do this, but if you are starting with a scan I would use a mesh program to first go over the pointcloud and tidy it up a bit, and if one is already there, they typically can do that cut/translate/fill as well.
amarilisppt
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Re: How to scaleup a .step object in only one direction?

Post by amarilisppt »

Thanks. Very interesting comment.
What type of free mseh software would you recommend for that operation?
What do you call the "pointcould"?
Thanks agsin.
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