Complex Sections

[aapo]

I'd really like to get it working for profiles and section normals not on the XY plane before merging. "It's done when it's done".

Oh yes, that's a fair point. That kind of changes could have an effect on the data format, or the general data structure of the feature, so it's probably indeed best to publish it only after it's fully ready.

[wandererfan]

...except that the hatchings in example 4 (re-attached) have some weird problems with circular disks at the fillet sections (see example pic).

Hatching works now on your sample and profiles/section normal not on XY plane is also working, I think.

Left to do:
- marks at "inflection points"
- perspective projection. the projection produces a result, but there are hatching issues.
- profiles with curves. this works for single projection strategy. Piecewise produces an unhatched result or fails.

I'm not sure how useful perspective or piecewise curved profiles are in real life.

[aapo]

Hatching works now on your sample and profiles/section normal not on XY plane is also working, I think.

Left to do:
- marks at "inflection points"
- perspective projection. the projection produces a result, but there are hatching issues.
- profiles with curves. this works for single projection strategy. Piecewise produces an unhatched result or fails.

I'm not sure how useful perspective or piecewise curved profiles are in real life.

Great! So, almost everything is working already. I agree that perspective or piecewise curved profiles are not useful in practice. Inflection point marks are useful and standardized, though, so I think that's the only thing that's actually missing.

Thanks for this great feature!

[FBXL5]

I agree that perspective or piecewise curved profiles are not useful in practice.

+1

Inflection point marks are useful and standardized

But I'd like to have an option to switch them off, and the start/end marks of the section lines, too.

And the Section line should be extended past the arrow positions. But this can be achieved by the start/end marks, and they could be integrated in the arrow symbol. At the front for "pushing arrows" or at the rear for "pulling" arrows.

[wandererfan]

But I'd like to have an option to switch them off, and the start/end marks of the section lines, too.
And the Section line should be extended past the arrow positions.

Done and done. Is there a rule for the size/thickness of the marks? I've made the size proportional to the arrowhead size (25% for each leg) and the thickness proportional to the section line width (200%).

[FBXL5]

Is there a rule for the size/thickness of the marks?

I have no clue, But it should be in relation with TechDraws line width group preferences which defines 3 thicknesses: thick, thin, and graphic
Thick, the defining thickness used for outlines.
Thin is used for hidden (dashed) lines, and center and section lines (dot-dashed). its thickness is one half of the thick value.
Graphic is in between for dimension numbers and units, and annotations.

Thin dot-dashed lines should be fine with several standards -> read thin value from preferences. I would then read the thick value for the marks (= the 200 % you mentioned). I remember that I have seen thicker marks, but I think they were too heavy for thin section lines.

Arrowheads varied a lot even within one company. Some departments used "pushing" arrows others the "pulling" ones and with different head lengths and head angles. Sometimes the have the same shape as the view arrows that define a view direction.
And some demanded open arrowheads other closed or filled ones...

But I like your proposed Arrows so far and the marks too. Maybe the angle marks should be longer, but I'm not sure about that.

[rock.vice]

I do not know if the ISO standard set explicit rules, but I think that the drawings provided by "domad" can be considered really close to the examples provided by some reference textbooks of technical drawing.

[FBXL5]

Having another quick look at the thread I wondered if we are talking about one or two new tools.

I'd prefer two separate tools:
- one for several parallel offset sections (ignoring the perpendicular connetions)
- one for angled section planes

And both shouldn't be mixed as in the example.

A single tool should have a toggle to perform either only parallel or only angled sections.

[wandererfan]

How about this?
- ProjectionStrategy = Single. Much the same as a regular section, except it uses a profile instead of a section plane. All projections are made according to the SectionNormal.
- ProjectionStrategy = Piecewise. Every segment in the profile generates a face in the result; Projections are based on profile segment normals.
- ProjectionStrategy = NoParallel. As Piecewise, except profile segments that are parallel with the SectionNormal are ignored. This would do your "several parallel offset sections" if the profile only contains vertical and horizontal segments.

I'm confused by "one for angled section planes". The current section view will do angled sections. The data entry is awkward, but I'm working on that.

[aapo]

How about this?
- ProjectionStrategy = Single. Much the same as a regular section, except it uses a profile instead of a section plane. All projections are made according to the SectionNormal.
- ProjectionStrategy = Piecewise. Every segment in the profile generates a face in the result; Projections are based on profile segment normals.
- ProjectionStrategy = NoParallel. As Piecewise, except profile segments that are parallel with the SectionNormal are ignored. This would do your "several parallel offset sections" if the profile only contains vertical and horizontal segments.

Ooh, that would be perfect!

Although, I'm not sure about the name "NoParallel". Some people would call it "NoPerpendicular" (i.e. not perpendicular to the projection plane). I'd name it "PiecewiseExcludeNormal", as it's a modification of piecewise strategy. Also, this projection strategy would be non-standard, but I agree that it'd cool to have a mode that could be used to make something exceeding the current conventions. FreeCAD TD would be on the leading edge, finally!