Error in Basic Modeling Tutorial?

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Gravydog
Posts: 12
Joined: Thu Dec 05, 2019 2:49 am

Error in Basic Modeling Tutorial?

Post by Gravydog » Sun Dec 08, 2019 1:54 am

I'm struggling enough without the operations in the tutorial not having the correct effect. In https://www.freecadweb.org/wiki/Basic_m ... utorial/en, after I create the angle iron they say: "Don't want the angle oriented that way? You just need to change the placement of the Box001 shape. Select it, unhide it, and in the Data tab, click on the + in front of Placement, then expand the Position parameter, and change its X and Y coordinates. Hit Enter, hide the Box001 shape again, and your angle orientation is now different."

This just moves the object along the x or y axes, it doesn't rotate the object around the z axis for me as the drawing appears that I wanted, changing "Angle" does that for me. Does the tutorial need correction or clarification or is it just me?

Trying "Axis" does really weird things, like when clicking x or y the object jumps like 90 degrees with the first click of the increment arrows and then smaller and smaller changes as the number grows greater. And somehow in my bumbling around I keep creating extra copies of the object on the screen that don't appear in the Model pane. Sometimes I can delete them, sometimes a warning, sometimes I can't delete them. I'll have to look into "Axis" more.

Rob
chrisb
Posts: 21222
Joined: Tue Mar 17, 2015 9:14 am

Re: Error in Basic Modeling Tutorial?

Post by chrisb » Sun Dec 08, 2019 6:49 am

The word "angle" has a twofold meaning in that tutorial. Especially in that paragraph it should say "iron angle" instead of "angle". If you want to turn the iron angle you can do this in the data tab as well: RotationAxis tells you around which axis to turn: (1,0,0) for the values x, y, z respectively means you turn around X-axis, (0,1,0) around Y-axis, (0,0,1), which is the default, around Z-axis. The angle indicating how much it is turned is above the RotationAxis. If more than one direction has a value different from 0 the rotation axis lies in between.

If you want to turn it arbitrarily it is often easier to imagine if you use so called Euler angles, i.e. turn your object around X-axis, then around Y-axis, and finally around Z-axis. For that there is the PlacementDialog, which you enter when clicking on "Placement" in the DataTab, and then on the three-dots-button occurring at the right. If you check the "Incremental" box you can subsequently turn around single axes and apply.

See the Placement documentation in the wiki.
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