how to from picture to 3D model ?

[janjos]

Hi FreeCAD users,

Last week I bought a Creality Ender 3 V2 printer.
Yesterday my wife asked me to print a 3D model of the logotype of her company, see attached picture.
It is just a ring with inside what looks like a H letter and again the same but upside down.
I started looking for a software where I could create a 3D model of this picture, export to STL, and using Ultimaker CURA slice it to gcode.
Searching the www I found FreeCAD.

On my Win10 desktop I downloaded, unpacked and started the portable FreeCAD version 0.18.

After reading and watching a few tutorials I started my project, using at first "Part design" workbench.

I created a Body, then a sketch on the XY plane, drew two circles of 100 and 90 mm radius and the same center point to form the outer ring of the model and in Tasks clicked "Pad" of 10 mm length. I got (the outside) a ring.
I then clicked the top face of the ring and created a new sketch.
On this new sketch I created 4 rectangles, adjusted the short sides of the longer ones so they fit inside the outer ring, clicked pad, 10 mm length, reversed.

In the same sketch I created two circles to form the bend leg of the H.
The idea was then to trim everything so I only get the required pieces of the smaller rectangle and both circles.
Unfortunately after many hours, much www search and watching tutorials, I do not succeed. FreeCAD gives errors when trying to pad, the trimming does not create closed objects, ...
I also tried using the Part workbench for this job but don't know how to remove/trim away the unnecessary pieces of the inner circles.
See attached the result of what I have up to now.

Questions:
Should I use Part design or Part workbench ?
Using one or the other can someone please point me in right direction so I can have a working model to export to STL, slice it, 3D print it and ultimately make the wife happy ?
Thank you.

Best wishes,
Janjos

[chrisb]

Hi and welcome to the forum!

You didn't include the sketch which could not be padded, so there is nothing we can say about it. Please upload that.

I would definitely use PartDesign for this. The logo is symetric, so you can model just the half of it and then make a polar pattern.

[chrisb]

Here is a proposal how it could be done

SnipScreenshot-b1e558.png (20.99 KiB) Viewed 209 times

[drmacro]

A couple different takes:

Snip macro screenshot-45b7e4.png (318.9 KiB) Viewed 192 times

[M4x]

Maybe this could be interesting for you too. https://watchguy.co.uk/a-new-era/

The guy created a thread in the showcase forum too.

[janjos]

Hi Chrisb,

Thank you.
Up to now I just download your file, using FreeCAD exported it to STL and with Ultimaker CURA sliced it to get the gcode file that 3D printer is now printing.
I still need to analyze in detail your FreeCAD drawing.
I did see that you also used different sketches. One for the outer ring, one the rectangles and one for the bend leg.
The sketch with the bend leg, I noticed that it is all nicely constrained and it has some reference lines.
I suppose that was a must to be able to pad it.

@drmacro
Thank you too. I did not look into yours yet has from the print screen on your post the bend leg does not look like the original logo.
However I will also use it as a learning reference.

Finally thank you to all the developers of such an excellent software.
Today I already recommend it to some colleagues from the chemistry department of the Ghent University (https://www.chemistry.ugent.be/we/chem/we06)

Best wishes,
Janjos

[chrisb]

Good to se that it was useful.

I did see that you also used different sketches. One for the outer ring, one the rectangles and one for the bend leg.

I reused your sketches. On my own I would have made it from at most two sketches. It is not always good style to put all geometry into one sketch. It is better to use too many than too less, but in this case it is simple enough. Just as an exercise for you: try to model the whole logo in a single sketch. Make sure you have only closed paths, no crossings, no T-joints.

The sketch with the bend leg, I noticed that it is all nicely constrained and it has some reference lines.
I suppose that was a must to be able to pad it.

it is not a must, but a very strong recommendation to fully constrain your sketches. There are very few exceptions, e.g. if you have traced some amorphic organic image with B-splines.

[drmacro]

...
I did not look into yours yet has from the print screen on your post the bend leg does not look like the original logo.
However I will also use it as a learning reference.

I simply imported the image you provided and traced over it. There was no attempt to duplicate it precisely.
So, no, you should NOT expect it to be printer ready.

It is not meant to be printed, it is meant to provide examples you can learn from.

[chrisb]

To get you going: this is a start so that you can see the you have to split the circle into arcs in order to avoid crossings: