Basic Part Design Tutorial

[chrisb]

I am sorry to be late and I am especially sorry if I have created addional work. I had rebuild the basic tutorial some time ago, but could not lay hands on it during the last two weeks because it was on a different computer. I wasn't even sure if it still exists, but it did. I had made the following changes to the model compared to quick61's:

• I omitted the symmetry constraint in the first sketch. There is no symmetry involved, and the symmetry constraint is still problematic for the solver. See below for a better usage.
• I placed Sketch001 on a base plane
• I placed Sketch002 on a base plane. The external reference uses Sketch001 instead of a face.
• The Length of Pad001 should be defined by means of an Expression, but not for a newbie. I would mention the possibility and give a link.
• I summed up all mirrors into one.
• For the Sketch003 defining the square in the middle I used the symmetry constraint, because it is most sensible to use it for centering rectangles.
• I placed the Sketch004 directly on the XZ plane.
• Set Refine property in the last step to True.

Concerning Harrys proposal I would vote at least for the following changes:
- Leave preferences at their standard: line color, refine property
- Since it is a basic tutorial I would not introduce DatumPlane yet

Perhaps it is sensible to have two versions of this object, one being Harry's basic tutorial for newbies and 0.16ers, and another showing how it could be made more robust, which might need some more love than I put into it.

[wandererfan]

Who's driving this bus???

https://www.freecadweb.org/wiki/Sandbox ... torial_017

bpdt3.fcstd

(57.04 KiB) Downloaded 42 times

[HarryGeier]

I thought, we are still discussing where the bus drives to..

But when there are enough drivers around... i have no problem to wait for the next bus...

[ulrich1a]

I would construct the part from Quick61 in the new PartDesign with an approach similar to the Bearingholder tutorial. It starts with two datum planes. These datum planes are not really required for this part, but they do show the approach. I am using datum lines, in order to provide the external geometry for the pocket.

At looking at the picture, I see that the datum planes have a confusing visualization. It looks like, as if both datum planes are in front of the part, but one is constructed behind the part. This seems to be a bug in the Tools/Save picture ... function.

Ulrich

[chrisb]

bpdt3.fcstd

Your model shows a "not a DAG" error. What have you done to create this?

[chrisb]

It starts with two datum planes. These datum planes are not really required for this part, but they do show the approach. I am using datum lines, in order to provide the external geometry for the pocket.

I like the approach of having the same example for demonstrating different modeling techniques. However having a DatumPlane being the same as the XZ plane makes it obsolete, why not use the XZ plane directly?
If the tree is shown in the tutorial, it should reflect the dependencies, i.e. you should reorder the elements so that Sketch001 is above Sketch in the tree, and of course, they should swap their names.

It looks like, as if both datum planes are in front of the part, but one is constructed behind the part.

I don't have any problems here, I only get the view as seen in BasicPartDesignTutorial_screenshot.png.

OS: Mac OS X
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.13483 (Git)
Build type: Release
Branch: (HEAD detached at 0ac3246)
Hash: 0ac32464e45fa9648cdaf702ebda06650dabe9dc
Python version: 2.7.14
Qt version: 5.10.1
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: German/Germany (de_DE)

[ulrich1a]

However having a DatumPlane being the same as the XZ plane makes it obsolete, why not use the XZ plane directly?

As I started the construction, I had both datum planes in my head, because I wanted to have them. You are right, both datum planes are not really needed here. When making a tutorial out of it, it is possible to show them as a framework. So its more a question about, what should be shown in the tutorial. One can easily say, that it is also possible to use the standard planes.

I don't have any problems here, I only get the view as seen in BasicPartDesignTutorial_screenshot.png.

The problem with the view is not in the display, but in the image created with the Save picture... function. Did you made a picture from the design and had a look at the picture?

I am having the problem with a windows-version as well with a Debian based version.

Ulrich

OS: Debian GNU/Linux 9.4 (stretch)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.13489 (Git)
Build type: Unknown
Branch: Rueck6
Hash: 553f9d01f55ad0277b3d8df02e8fc08e0bea8b80
Python version: 2.7.13
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.1.0
Locale: German/Germany (de_DE)

[chrisb]

The problem with the view is not in the display, but in the image created with the Save picture... function. Did you made a picture from the design and had a look at the picture?

I cannot make a "Save picture" at all, I only make Screenshots. That's probably some problem with some Mac drivers. We had discussed it somewhere else.

[GeneFC]

At looking at the picture, I see that the datum planes have a confusing visualization. It looks like, as if both datum planes are in front of the part, but one is constructed behind the part. This seems to be a bug in the Tools/Save picture ... function.

I can verify that behavior.

I saw the problem in every type of "Tools > Save Picture" format.

I did not see any problems with screen captures, exports, or PDF files.

OS: Windows 7
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.13488 (Git)
Build type: Release
Branch: master
Hash: 2891173923bcecaace64e0544f5773facbdef436
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.1.0
Locale: English/UnitedStates (en_US)

Gene

[NormandC]

Okay, I can confirm the datum plane issue with FreeCAD's save picture utility when using the standard blue gradient background. But! No issue if I choose a transparent background:

FreeCAD's save picture utility with transparent background.

BasicPDTut_screen_cap_02.png (39.05 KiB) Viewed 1179 times

The image was edited in Gimp only to crop it.