[Solved] Need help recreating a simple shape

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pathfinder
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[Solved] Need help recreating a simple shape

Post by pathfinder »

Hello all,

First i thought I'd just use FreeCAD to import stuff I built in Blender to create gcode, but I got intrigued and want to learn using FreeCAD as an actual modeling program. So I gave myself the task to recreate a shape I built in Blender:

Image

My goal is to build this as a single solid.

What I tried was building one of the six segments(sketching the crossection, Part -> Extrude, Part -> Boolean with a rotated rectangle to get the angle right), then copy and rotate it until I have the shape, then join them all using Part -> boolean and adding chamfers to it:

Image

Image

Image

Image

The issue is that the boolean didn't really join the parts to one big solid, but kept the inner faces intact, so the chamfers didn't work as intended:

Image

I know this behavior from Blender; I guess the boolean can't really handle two points in the same position, but needs actual overlap to work. The issue is that I don't know how to precisely create this overlap. I also tried using Draft -> Rotate, but it seems like I can't insert precise values without having them overwritten by mouse movements…?

Another route I tried was rebuilding the hexagonal outlines with Curves -> JoinCurves, but I'm not sure how to build a solid from it and it seems like a workaround rather than a good workflow.

Image

I'm pretty sure there's a multitude of way to get to a result, so, how would you build this?

Also, this is just a small side question, but is there something a bit more similar to Blender style transformation? What I mean is, in Blender, if I want to move an object, let's say by 10 units along the x-axis, I'd just type G, X, 10. Same with rotating along an axis being R, X, 15 for 15 degrees around the x-axis or S, X, .5 for scaling. Is there something similar? The transform tool feels a bit clunky, especially if I want to rotate or move a precise amount.

Edit: forgot system information:

OS: Debian GNU/Linux 9 (stretch) (openbox)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 2021.1015.24301 +4280 (Git) AppImage
Build type: Release
Branch: LinkDaily
Hash: 556c87868ea46796242156e9f73eae98259794b7
Python version: 3.9.7
Qt version: 5.12.9
Coin version: 4.0.1
OCC version: 7.5.2
Locale: English/United States (en_US)


TIA
Last edited by pathfinder on Fri Oct 22, 2021 6:07 pm, edited 2 times in total.
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thomas-neemann
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Re: Need help recreating a simple shape

Post by thomas-neemann »

pathfinder wrote: Fri Oct 22, 2021 10:35 am
I would do it this way. fast but not fully parametric

https://www.youtube.com/watch?v=5IsSKn0xFuc

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pathfinder
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Re: Need help recreating a simple shape

Post by pathfinder »

thomas-neemann wrote: Fri Oct 22, 2021 11:46 am
I would do it this way. fast but not fully parametric

https://www.youtube.com/watch?v=5IsSKn0xFuc

Hey, thanks for the answer.

That is an interesting approach, this will definitely something I'll try in the future, but for this, it changes the original model too much; especially the chamfers are even all around on the original, while they are getting smaller towards the inside of the hexagon shape here.

Also, kudos for putting so much effort in it, making a video and all. I just realized I really need to get more familiar with the Draft workbench, I really overlooked it before.
Last edited by pathfinder on Fri Oct 22, 2021 12:20 pm, edited 1 time in total.
drmacro
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Re: Need help recreating a simple shape

Post by drmacro »

As you've found already the modelling paradigm is different when comparing FreeCAD and Blender.

The operations like placement and movement are distinctly different. Blender is, primarily, an art tool, so grabbing a loop or tile and dragging in space or specifying a direction and magnitude are the norm.

In FreeCAD placement and movement are more attuned to placement/moving a whole solid. And, the shape changing is done in the creation of that solid.

You apparently have found the Transform tool and noted it can adjust the placement by increments specified in the Transform dialog. Native tools for placement are found in the Edit menu and provide granular movement/placement. When adjusting solids to mate with each other, I typically use the Manipulator workbench.

As for your example, I offer an addition way to accomplish the task, using Part Design workbench and the sweep (or Additive pipe). It could also be done with the Part workbench Additive pipe as well.:
Snip macro screenshot-d63d9f.png
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pathfinder
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Re: Need help recreating a simple shape

Post by pathfinder »

drmacro wrote: Fri Oct 22, 2021 12:19 pm You apparently have found the Transform tool and noted it can adjust the placement by increments specified in the Transform dialog. Native tools for placement are found in the Edit menu and provide granular movement/placement. When adjusting solids to mate with each other, I typically use the Manipulator workbench.

As for your example, I offer an addition way to accomplish the task, using Part Design workbench and the sweep (or Additive pipe). It could also be done with the Part workbench Additive pipe as well.:
Hello,

I wasn't aware of the option in the edit menu, this is very helpful, thanks.

I know that Blender works very differently. I wasn't talking about moving single vertices around, though, it was more of a workflow question. I can move, rotate or scale whole objects in both programs, but in Blender, it's a matter of pressing three to four buttons, while in FreeCAD, it needs interaction with a dialog window. I'm not saying one is better than the other, it's just me being used to one and wondering whether there happens to be something similar in FreeCAD.

As for the object itself, while the approach is interesting and will definitely go into my repertoire, for the task at hand, it doesn't work. The chamfers of the original model have the same radius all around, while they don't in this approach.

Thanks for your time.
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Re: Need help recreating a simple shape

Post by drmacro »

pathfinder wrote: Fri Oct 22, 2021 12:37 pm ...
I know that Blender works very differently. I wasn't talking about moving single vertices around, though, it was more of a workflow question. I can move, rotate or scale whole objects in both programs, but in Blender, it's a matter of pressing three to four buttons, while in FreeCAD, it needs interaction with a dialog window. I'm not saying one is better than the other, it's just me being used to one and wondering whether there happens to be something similar in FreeCAD.
The transform tool is the closest to the "free form" Blender way. There are FreeCAD keyboard shortcuts (though, none predefined for the tools we are discussing. Shortcuts can be defined in Tools>Customize.)

As for the object itself, while the approach is interesting and will definitely go into my repertoire, for the task at hand, it doesn't work. The chamfers of the original model have the same radius all around, while they don't in this approach.
...
I don't see your point...but, I've not stared at your example in order to discern what you mean.
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pathfinder
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Re: Need help recreating a simple shape

Post by pathfinder »

drmacro wrote: Fri Oct 22, 2021 12:47 pm […]
I don't see your point...but, I've not stared at your example in order to discern what you mean.
Sorry for being not more specific, this shows what I mean:

Image

Please ignore the mess of the original model, It's an imported mesh.
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Re: Need help recreating a simple shape

Post by thomas-neemann »

pathfinder wrote: Fri Oct 22, 2021 1:00 pm

I forgot to press the recording button. so it could fit
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pathfinder
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Re: Need help recreating a simple shape

Post by pathfinder »

thomas-neemann wrote: Fri Oct 22, 2021 1:23 pm
pathfinder wrote: Fri Oct 22, 2021 1:00 pm

I forgot to press the recording button. so it could fit
Aah, ok, so basically building the edges, then filling them in, huh? That's pretty good :)

Do you know how to turn this into a solid? I want to ultimately use the path workbench on this and I need it to be a single solid for it (Using Part -> Make solid only works on separate ruled surfaces)
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Re: Need help recreating a simple shape

Post by thomas-neemann »

pathfinder wrote: Fri Oct 22, 2021 1:40 pm
here is a possibility

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


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