Draw a line and make it snap perpendicular to another line

Hi all. The function i probably use the most when drawing in acad is to start the drawing of a line and make the endpoint of the line snap perpendicular to another line. Now, I have set the perpendicular option in osnap, and nothing else. But it's not snapping to the line, it snaps somewhere else.

I made a screenshot but can't figure out how tu upload it here.

The thing is, that I installed Bricscad on my laptop, and it worked there.

Here on my workstation it doesn't. And just now I tried acad on the workstation, and it doesn't work there either. I'm starting to think it has something to do with the drawing, or the layer that the lines i want perpendicular snaps to reside. Anyway, if anyone experienced something like this please share.

Regards,
Tom E. Øygarden

Comments

  • edit:
    i just opened up another drawing, and this behaviour worked as expected.

    So i guess the question is: what (in a drawing) can govern this behavior?

  • Hi Tom,

    Check the Z coordinates of the line that you are snapping to. If the ends of the line have differing Z coordinates, then the perpendicular snap will show up in unpredicatable places. It is not a bug but that is how perpendicular snaps are expected to behave.

    Regards
    Rakesh Rao
    http://www.4d-technologies.com

  • Hi Rakesh.

    The Z coords ar all zero, but I now got another hint.

    The perp snap works on lines but not on polylines.
    Is this intended behaviour. I guess I can convert the polylines to lines,
    but I don't logically see why the perp snap wouldn't work on a line segment.

    Anyways, thanks again for quick replies Rakesh!

    Regards,
    Tom E. Øygarden

  • Hm. I was a bit wrong, but here's the thing. Some lines on this drawing ar 2d polylines, perp snap works. But others ar 3d polylines. Here the problem arises, even though the z-coords ar zero. I have no idea why someone gave me 3d lines in this drawing though. Any quick way to convert all 3d (poly)lines to 2d (poly)lines?

    Tom

  • Solution: i just ran flatten on all the lines, and perp snap works like expected.

  • Tom, each vertex in a 3D polyline may have a different elevation. Try the LIST command or use the properties panel to step through the vertices as a check.

    If you are happy enough to convert from 3D to 2D polylines you can use the FLATTEN command.

     

  • Greg: Thanks for the 'list' tip. I opened an older version of the drawing, from before i flattened it. Ran list on a 3d pl and all z values were 0. So is it not possible 3o snap properly to 3d polylines even if they are on one plane, and the same on as the line that we want to snap?

    Anyway, i had no use for 3d lines in this drawing, so i just flattened all of them.

    Tom

  • Tom,

    Open your old drawing, before the FLATTEN command was run, and use LUPREC to set the precision to 8. See if some of the Z co-ordinates are slightly different to zero when viewed at maximum precision. This sometimes occurs and there was a bug in an earlier version of Bricscad that caused the Z values to move slightly off zero.

    Jamie

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