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Adjusting line length and angles in the Sketch



  • Tim Heeney

    Can you take an image of what you want to sketch out. Maybe do a rough sketch in MS Paint ( jpeg format ) and post here using the insert image icon.

    That will give me a clue.

    Youtube has fairly good DSM tutorials about getting started.

    If your using the new V5, using the new sketcher constraints might be a steep learning curve for a beginner, so i'd suggest using the previous method we had to draw. I'll tell / show you how to set that up that when you come back with your sketch.

    Take a peek  ' '

  • Matthias Fluor

    Edit: I tried out DSMs constraint sketching - I can define all the lengths I measured and can then move the thing around to get the right angles - that's what I needed. And without having to chase the other "6 missing constraints somewhere in your model". That's intuitive. But please read below anyway, if there would be a way without constraining it would be interesting as well.


    Thanks for your help :-)

    The constraining sounds roughly what would be helpful I think - I honestly had a hard time using them in FreeCAD ,that's why I went over to take DSM for a spin, no need to chase after all the constraints. I designed 1-2 things in OpenSCAD but found a "sketch and pull" to be easier (even though I'm a programmer).

    This is the front part of the sketch - the selected line is too short, so what I (intuitively) wanted to do is:

    1. Fix the point top left

    2. Fix the lower point of the selected line

    3. set the length of the line to the correct length, so only the line itself and the angle top left get adjusted


  • Tim Heeney

    Everything i say below refers to the traditional method of sketch creation. ( i use the the new constraints now so i'm a bit rusty)

    By checking 'Maintain Sketch Connectivity' , the movement of a curve or it's end points will drag along connected curves. Unchecking allows for un connected ( selected item only ) movement.

    The key to successful moves is ALL in the positioning and orientation of the move tool and curve or end point selection.

    Curves have end points. Selection of such allows dragging or changing it's value...

    Tab to select the length or angle in above example. Entering a value ( carraige return)completes command to all 'tab' values.


    Upon selection, individual or using drag boxing techniques (drag box  R-L , only completely encompassed entities are selected)

    ( drag box L-R , selects as R-L, plus any partially clipped entities are also selected).

    key M for move tool and tool appears in the center of the entities ( or group of them).

    Move the tool (central yellow ball ) to where the move needs to move from. Alt click to set a direction of move - choose a line. the Axis dir now highlights with a projected thin line . A mini tool bar appears, enter a value directly or choose a method from the tools - i used the ruler option.

     So far so good?

    Using mmb roll and Ctrl, it's possible to cycle through all possible local selections to the curser position. It's possible to select opposite faces of a model this way to avoid spinning the model around - very useful !

    Always watch what is being selected along the bottom bar - curve , curve point, body , 5 bodies etc.

    Selection of a curve point always orientates the red axis where a positive amount will increase it's length only.

    Dragging the move tool closer towards the curve end, so it's closer to the intended end than the curve mid point, will auto snap the tool exactly at end. This is very handy...

    Notice how with the the curve selected, unlike the end point selected, the red arrow doesn't alter direction.

    Hope this all helps...


  • Matthias Fluor

    Thank you so much for the in-depth explanation! That's what I call high quality help :-)

    All makes sense, I tried it out and it works nicely.

    I think I stay with the Constraint mode now, as it's not as cumbersome as in the other mentioned software. I managed to create two parts with that pretty quickly with the needed sketch flexibility.

  • Tim Heeney


    I use the new constraint method nearly all the time now. DSM version is behind the Ansys current version so you may find you'll have to use the non constraint technology for certain shapes.

    Still, the future and all that plus it's a bit more of an interesting challenge - remember, the target result is what you're after. An unconstrained or partially constrained sketch is just as beneficial to progress to the next decision as a fully constrained sketch, which may take much longer to define. The more a sketch is defined / constraint applied etc, the more rigid it becomes. the less flexibility you have to make radical changes.

    Good luck with DSM...



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