topic Re: line drawn at origin fully constrained, no icon in Fusion Design, Validate & Document Forum

line drawn at origin fully constrained, no icon

kmanuele — Mon, 02 Oct 2023 21:21:58 GMT

Create a new sketch, draw a line starting at the origin. It becomes fully constrained, and I can't move it. I can shorten it via dimensions.

Fought with this for a while then found that it has a coincidence constraint whose icon is not shown in the browser -- only in the right click menu when editing the sketch.

Lesson? Don't use origin as an origin?

Re: line drawn at origin fully constrained, no icon

jhackney1972 — Mon, 02 Oct 2023 21:28:38 GMT

Your model should be related to the Origin, either directly to it or dimensioned and constrained to it. As you can see in the animated GIF there is not issue with a line to the origin and then moving it. At the end I add a horizontal sketch constraint to the line and still and grab the end and move it.

Re: line drawn at origin fully constrained, no icon

kmanuele — Mon, 02 Oct 2023 21:57:01 GMT

Not sure what you are doing that is different than me.

If I create a new design, create a sketch on one of the planes, draw one or more lines from the origin. The coincident constraints are not shown on the screen, and I can't move either line without deleting the coincident constraint in the context menu.

I've attached a simple file. Can you move those lines without deleting the (not shown) constraint?

Re: line drawn at origin fully constrained, no icon

jeff_strater — Mon, 02 Oct 2023 21:59:27 GMT

You answered it yourself: " It becomes fully constrained, and I can't move it. I can shorten it via dimensions."

The fact that you can shorten it with dimensions is what is preventing the entire sketch from being constrained. The line is constrained if it starts at the origin and is horizontal or vertical, but the other endpoint of the line is not constrained, which is why you can affect it with a dimension. Add that dimension, and the sketch is fully constrained.

Re: line drawn at origin fully constrained, no icon

jeffescott — Mon, 02 Oct 2023 23:03:10 GMT

Fusion adds constraints when you click on certain things. Not so with other things you just have to get used to it.

Usually speeds things up, but it can get confusing at times

Re: line drawn at origin fully constrained, no icon

kmanuele — Tue, 03 Oct 2023 00:19:51 GMT

I was simply trying to move (off the origin) a line that had no apparent (visible) constraints, even after removing any visible constraints from those fully constrained black lines.

It seems that for sketch items originating (or terminating) at the origin, the coincident constraint does not show up on the screen when hovering. It only shows up in the context menu. I eventually realized this.

It seems that the origin has special properties here (what happened to relativity ?? 🤔). Draw a line to the origin and extend it beyond. You can move the line but can't shift its orientation away from the origin (like a black hole 😃), and you can't delete the coincident constraint.

Also, during this I found that a line drawn on axis to the origin (rather than vice-versa) does not show a horiz/vert constraint except in the context menu.

Thanks for the responses. Please take mine as good-natured dialog, trying to learn.

Re: line drawn at origin fully constrained, no icon

jhackney1972 — Tue, 03 Oct 2023 00:47:54 GMT

If you have a line sketched from the Origin, you can easily find and delete the Coincident constraint if you select the line, near the origin end, right click and select Delete Constraint from the context menu.

Re: line drawn at origin fully constrained, no icon

TrippyLighting — Tue, 03 Oct 2023 11:13:09 GMT

@kmanuele wrote:

Lesson? Don't use origin as an origin?

Not quite. What I'll write is not a hard rule as there are always exceptions that yields another method, however any sketch should reference either the sketch origin or geometry projected into the sketch form other sketches, or edges of 3D geometry.

If you don't want to constrain a particular sketch element to the origin, then don't start at the origin as it is clunky to remove, as you have discovered.

Re: line drawn at origin fully constrained, no icon

kmanuele — Tue, 03 Oct 2023 17:23:53 GMT

Agree, designs (sketches) should have a reference point. I just didn't expect this behavior from Fusion

thanks