unexpected results when making cuts

[AdamTimm]

If this is my stupidity feel free to tell me. I have a good sense of humor.

I am practicing making cuts and in this case designing a new coffee measure for my morning coffee. To do this I needed to cut a sphere in half to start. The following is a photographic record of what is happening.

coffee measure 1.jpg (97.98 KiB) Viewed 2078 times

coffee measure 2.jpg (101.23 KiB) Viewed 2078 times

coffee measure bottom.jpg (100.72 KiB) Viewed 2078 times

coffee measure axonometric view.jpg (88.86 KiB) Viewed 2078 times

coffee measure unexpected cut.jpg (91.71 KiB) Viewed 2078 times

I had a couple more images but they would not load. The sphere seems to protrude through the cube when viewed on top and bottom. Seen in transparency the sphere is okay and in proper placement. When I do the cut however all that is cut is 1/4 of the sphere. As bugs bunny would say, "Ehhhhh, What's up Doc?"

[lukasubo]

I have no problem here. I think the issue may be that your shapes are not actually moved. Try manually setting their positions in their parameters (select them in the tree, and then click the "Data" tab below the tree and to the right of "View").

You could also sketch a half circle in the Part Design workbench and revolve it 180 degrees. I've attached a FCStd file demonstrating both methods.

My FreeCAD version information is:

OS: Linux Mint 17.2 Rafaela
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.16.6703 (Git)
Build type: None
Branch: releases/FreeCAD-0-16
Hash: 2ce5c8d2e3020d05005ed71f710e09e9aa561f40
Python version: 2.7.6
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17

[bejant]

No problem here either. In the last image it looks like Cube and Sphere have moved back to their default locations.

I had a couple more images but they would not load.

The limit is 5 attachments per post.

You don't even need to cut the Sphere with the Cube. Select your Sphere, and in the Data Tab change the Angle3 property from 360 degrees to 180 degrees. The Sphere will open up at the seam, then just rotate it -90 degrees about the X axis using the Placement property.

[AdamTimm]

Thanks guys!
I had the insight that I am learning a new language with FreeCad with which I have to speak to the program. Obviously, I am having slight communication difficulties and appreciate the input. I'll copy and paste your comments to my collection and will be trying to implement tonight.
I have been attempting to use the "Data" to manage part positions. I'm looking forward to seeing what your suggestions result in.

Adam

[AdamTimm]

Bejant,
You mentioned "default position." How do I tell the parts to "stay put?" How do I anchor the parts?
One thing I think FC should have is a "print preview." That way I could make adjustments before I set the cut or print. EG maybe something would be a "pre-cut" view so one could know if parts will "jump back."
I take it FC is basically WYSIWIG but has a bit to go before parts won't "default?"

[bejant]

Thanks guys!

You're most welcome!

I had the insight that I am learning a new language with FreeCad with which I have to speak to the program.

Yes your insight is correct and yes we need to learn how to communicate correctly with FreeCAD so you have to learn how to do that.

I have been attempting to use the "Data" to manage part positions.

For the wiki page see here:
http://www.freecadweb.org/wiki/index.ph ... _Placement

are you using the Placement widget:

or using the Placement Property directly from the Data Tab without clicking that 3 dot button [...] hi-lighted in red in the above image?

Bejant,
You mentioned "default position."

Not what you asked but the default position of Part WB > Cube, Cylinder, Sphere, (truncated>>>) Cone, Torus is related to the Origin ( X, Y, Z = 0). To see this, create a new document (File > New, or Ctrl + N, or click the Toolbar button), and in the Part WB choose the tool button that applies to each of the previous solids I've mentioned and see their relative positions in the 3D space.

How do I tell the parts to "stay put?"

They all stay put unless you change the location (deliberately or accidentally).

How do I anchor the parts?

I'm not sure I understand what you mean here because the parts are anchored already unless you move them somehow.

One thing I think FC should have is a "print preview."

Usually what you see in the 3D window is your output and so you would not want to Export anything I've seen in your images. Some people make the mistake of selecting everything by using Ctrl + A in the hierarchy tree so don't do that (and also it doesn't apply here).

To make a Cut of the Sphere and end up with the result you want, you need to move Cube. In your model I would do that by directly changing the Placement Property of Cube (see the image I linked t above). Don't delete Cut - instead move Sphere and then Cut will update.

EG maybe something would be a "pre-cut" view so one could know if parts will "jump back."

I think that the object will move in the 3D view as the Placement Property values are changed if you're in the Placement widget (the image above).

I take it FC is basically WYSIWIG but has a bit to go before parts won't "default?"

Yes FreeCAD is WYSIWIG but somewhere you're not understanding something and so are doing something wrong...

FYI: I can't reply back for half a day or so from this post.

[AdamTimm]

Placement widget...Yep! I'm getting good at radius, height and thanks to you Angle. That makes it fun but look at the results.

The sphere and cut out worked great, however....

coffee measure 3.jpg (100.54 KiB) Viewed 2014 times

This is what I am trying to do. I didn't join the parts. This is what I am getting in order when I try.

coffee measure union.jpg (98.42 KiB) Viewed 2014 times

This was from trying the intersection. The half cylinder invades the sphere.

It gets back to how to anchor the parts where I want them. "Hey FC I didn't want you to move the parts! Keep them where I want them!" The last image is close but I didn't "tell FC to move the half cylinder" into the hollow sphere.

[NormandC]

Hello Adam,

I think all your placement troubles come from the fact you've not checked "Apply incremental changes to object placement". I always check it beforehand, it's a nuisance that the setting is not saved.