Copying irregular shaped object help

Ok i give. I need some help from some better modelers than I. I’ve spent about 8 hours so far, and feel like I’m simply taking the wrong approach. I’m in a mess of rhombuses that wont loft together, and when they do, don’t make a manifold object. Can someone give me some guidance on how to approach copying the attached object with all these planes?

In Prototyping/Reversing my mandates were form, fit and function.

Have you mapped the mountings and openings?

A few more pictures would be helpful.

I’d probably start with the most common shape which appears to be similar to a rhombohedron. Then use the Boolean tools to add and subtract from there. Worry more about the outward shape and then work on the internal cavity. using the shell tool first and then subtract the other openings.

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The Rhombohedron I see is the opening your thumb is at and the one opposite.

What is the manifold’s function? Just air flow?

that’s a simple square where my thumb is. the challenging shapes for me are in the center of this image, and the opposite side in the following pictures. (couldn’t post more than one because my account is new)

to your point, maybe i should start over with a solid shape and go from there. I probably started too early with shaping the thickness of the walls.

Here are two more pictures. and also, yes, it’s for mounting a fan for a 65 buick regal.

and yes, sorry. i’m pretty good with measure/reproduce for the hole locations, etc. so that is solid on my end.

Cool project. Yes I’d start as a solid and shell it from the bottom (ref last pic). and then subtract the other openings. Is there a butterfly valve/vent in there? If so that is the only thing and makes the shape imperatively exact.

thanks, yeah it should be cool when it’s done. i plan on printing it with nylonX. and there might be a flap on this one, there’s a larger piece thats about 12" that the blower fan mounts on.

in other words you can fudge the shape a bit, concentrating on the openings/flow as the important feature, within reason of course. if there is a critical valve then no fudging the shape.

Parts like that are molded and so the shape is somewhat dictated by the mold maker. Us “Printers” do not have to worry about the injection mold process unless the part is going to production as molding is still cheaper than printing at this time.

My first case project (no exp.) was sent back, telling me I needed draft. So I had to learn what that was. Lead me to a great article about designing for the Mold Maker. I need to find that article, it was 10 years ago but the advice was solid!

When you work for a small company, one day you can be sweeping the floors and the next deciphering someone else’s crappy code trying to find the design flaw.


I have no idea what those dimensions are. But I took your photo and traced the profile, at an arbitrary scale and extruded that. And then tried to move edges to a general proportion. I have a “flange” part that is separate to make the rest of the body easier.

I think maybe this path is workable to solve the problem you have.

Steps that I think can get you close

  • Trace profile or measure it and draw it
  • select edges and move to fit proper mesurements
  • Add top extrusion with hole in it then cut hole
  • Chamfer all the parts
  • shell from front
  • cut other holes
  • project opening edge onto flange
  • cut hole in flange

Shapr3D Project File: airVent.shapr (5.9 MB)

This is what mine looks like. Not great but was hard from the photo alone:

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Thanks! i’ll take a look at what you did. and also reply when i have another go at it, working general to specific like everyone has said.

i took a look at your model, and have a question. how did you get the smooth sides that bulge and twist at certain areas? they seem to not be butchered like what i came away with, and look to be “in control.”

This is not really your part I just drew some random lines in a rough quick approximation… But…

Here is a video where I select an edge and “move” it to get those shapes you mention. This is also a demonstration of how I did the shell and get the “other two” openings.

But my thought is if you put some sketches of your actual measurements you can drag those areas to get pretty close to what you want.

I think an important key step for all this is to get the outer part as close as you can before you shell it.