Techdraw - no center snap points are shown

Discussions about the development of the TechDraw workbench
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71GA
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Techdraw - no center snap points are shown

Postby 71GA » Mon Aug 05, 2019 6:26 am

I am trying to dimension a rod in a Techdraw with a bunch of screw holes, but i can't, because there is no snap points in the middle of the circles. Why are they instead drawn at the side of the circles? Also there are none drawn for hidden edges (circles or straight lines)!

How to overcome this issue in Freecad 0.18? Is this fixed in 0.19?
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Screenshot from 2019-08-05 08-22-55.png
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Last edited by 71GA on Mon Aug 05, 2019 6:33 am, edited 1 time in total.
chrisb
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Re: Techdraw - no center snap points are shown

Postby chrisb » Mon Aug 05, 2019 6:29 am

Is this a Sketcher, Draft or TechDraw help request?
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71GA
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Re: Techdraw - no center snap points are shown

Postby 71GA » Mon Aug 05, 2019 6:33 am

chrisb wrote:
Mon Aug 05, 2019 6:29 am
Is this a Sketcher, Draft or TechDraw help request?
I added some details. It is Techdraw workbench.
chrisb
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Re: Techdraw - no center snap points are shown

Postby chrisb » Mon Aug 05, 2019 6:55 am

Moved to TechDraw forum.
wandererfan
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Re: Techdraw - no center snap points are shown

Postby wandererfan » Mon Aug 05, 2019 1:21 pm

71GA wrote:
Mon Aug 05, 2019 6:26 am
I am trying to dimension a rod in a Techdraw with a bunch of screw holes, but i can't, because there is no snap points in the middle of the circles. Why are they instead drawn at the side of the circles? Also there are none drawn for hidden edges (circles or straight lines)!
I see 1 circle in the screen grab and it has a center mark. I don't see other center marks.

A screen grab really isn't enough information to investigate this. Please post the model. If it is proprietary, pm it to me or make a simple version that shows the issue.
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71GA
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Re: Techdraw - no center snap points are shown

Postby 71GA » Sat Aug 10, 2019 8:43 pm

wandererfan wrote:
Mon Aug 05, 2019 1:21 pm
71GA wrote:
Mon Aug 05, 2019 6:26 am
I am trying to dimension a rod in a Techdraw with a bunch of screw holes, but i can't, because there is no snap points in the middle of the circles. Why are they instead drawn at the side of the circles? Also there are none drawn for hidden edges (circles or straight lines)!
I see 1 circle in the screen grab and it has a center mark. I don't see other center marks.
There is no red snappy point in the middle of the circle. How come you can't see it from the screenshot? It really is obvious... =)
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Kunda1
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Re: Techdraw - no center snap points are shown

Postby Kunda1 » Mon Aug 12, 2019 5:48 pm

71GA wrote:
Mon Aug 05, 2019 6:26 am
Is this fixed in 0.19?
You can test 0.19 and let us know. FreeCAD can work on the same machine with multiple versions in parallel.
Want to contribute back to FC? Checkout:
#lowhangingfruit | Use the Source, Luke. | How to Help FreeCAD | How to report FC bugs and features
wandererfan
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Re: Techdraw - no center snap points are shown

Postby wandererfan » Wed Aug 14, 2019 2:19 pm

71GA wrote:
Mon Aug 05, 2019 6:26 am
I am trying to dimension a rod in a Techdraw with a bunch of screw holes, but i can't, because there is no snap points in the middle of the circles. Why are they instead drawn at the side of the circles? Also there are none drawn for hidden edges (circles or straight lines)!
TD uses the traditional "+" for center marks. The center marks can be used as dimension end points.
CenterMarksAsDimEnd.png
CenterMarksAsDimEnd.png (11.15 KiB) Viewed 293 times
The Vertex (red in your case?) at the side of the circle is the start/end point of the circular edge.

Your circle is very small relative to the center mark. Are you having trouble selecting the center mark? The circle may be masking the selection area of the center mark. There is a CenterScale property in the view tab of the view that might make the mark small enough to be selectable inside the circle's selection area.

We don't have the ability to cycle through the objects under the cursor yet.
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71GA
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Re: Techdraw - no center snap points are shown

Postby 71GA » Thu Aug 15, 2019 9:34 am

wandererfan wrote:
Wed Aug 14, 2019 2:19 pm
TD uses the traditional "+" for center marks. The center marks can be used as dimension end points.
Ok I understand this and now I have one problem less. But center mark is only visible if you look at the hole from the top (!), but not from the side, so you can't dimension it's coordinates from the side (!) unless your view normal goes right through the...
wandererfan wrote:
Wed Aug 14, 2019 2:19 pm
The Vertex (red in your case?) at the side of the circle is the start/end point of the circular edge.
... mentioned vertex. Which is red in my case and in your case it is blue.

I saw in 0.19 development version that TechDraw workbench introduced a quadrupel of points which you can add to the circles. This is insufficent if you use angled (!) auxilary views. Because from the side you won't be able to dimension the hole no matter what you do. So some algorhythm should be created to detect the center of the hole and put a point there. This is very needed and it should also work for the "hard hidden" edges. Otherwise holes really become a nightmare to dimension.

I've never in my life struggled with holes as much as I do with Freecad TechDraw Workbench, but hey it is not all that bad. Just make sure you implement a snapping point in the middle of circles/elipses. The quadrupel of points presented in 0.19 is only a fix which doesn't work for angled views and doesn't solve the fact that algorithm for the circle center point is needed.

I suppose you already got the algorythm because you put a center mark there. But please make this center mark into a snappy point and make it visible from any angle and for hidden circles/elipses as well. You should make center mark optional like horizontal/vertical center lines are.
chrisb
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Re: Techdraw - no center snap points are shown

Postby chrisb » Thu Aug 15, 2019 12:35 pm

I am by far no expert in technical drawings but it seems very sensible to me what I learned so far: Dimensions should not be used in perspective drawings at all.