7 Replies Latest reply on Dec 12, 2016 11:25 AM by Don Carter

    red origin - what is the purpose ?

    Gerard Boterman

      What is the purpose of a red origin in a part drawing / sketch if it cannot be used or selected.

      Only the blue (model) origin can be selected and used in the sketch mode . . .

        • Re: red origin - what is the purpose ?
          Kelvin Lamport

          The red triad shows the location of the real origin relative to the sketch elements.

          And it is effectively selectable, albeit really a transferred coincident point to the real origin.

          • Re: red origin - what is the purpose ?
            Jim Wilkinson

            Hi Gerard,

             

            The sketch origin is useful for two things:

            • So you easily know where the 0,0 point of the sketch is, especially in the case where you are not on a plane that intersects the global origin (see Kelvin's reply).
            • So you know which direction is horizontal (short arrow on the origin) and vertical (long arrow) for sketch relationships.

            In most cases, the sketch origin is projected directly off of the global original of the part/assembly so the centerpoint of the sketch origin is the same as the centerpoint of the global origin when looking normal to the sketch plane. However, the short and long arrows of the sketch origin are only directly aligned with the global origin arrows if you are sketching on planes parallel to the front view. So the sketch origin is almost always useful for the vertical/horizontal orientation reference.

             

            Also, the sketch origin does not always lie in a position projected from the global orientation. There are several commands that can move and rotate the sketch origin (and geometry in the sketch) such as:

            2016 SOLIDWORKS Help - Modify Sketch Dialog Box

            and

            2016 SOLIDWORKS Help - Align Grid/Origin PropertyManager

            In these cases, it is especially important to understand the sketch coordinate system since the sketch origin point and horizontal and vertical may not be aligned to the the global coordinate system at all.

             

            I hope this helps,

            Jim

            • Re: red origin - what is the purpose ?
              Don Carter

              Gerard,

              I half agree with you - the red sketch origin is not always selectable.  If you have the blue global origin hidden, then you cannot select the red origin to dimension to nor to attach a relation to.

               

              With the blue global origin visible but with the model oriented so that you're not viewing normal to the sketch plane, then you get the same result: you cannot select the red origin to dimension to nor to attach a relation to.  See pic 1. The dimension shown is between the global origin and the line but is displayed as if were connected to the sketch origin.

               

              As Kevin indicated, you CAN attach geometry to the sketch origin.  See pic 2.

               

              Why can geometry attach to the sketch origin but not dimensions nor relations?

              I thought this was a bug.  I thought the sketch origin was always selectable.  But I found this in SWx 2015, 2016, 2017.

              It would be nice to have the red sketch origin always selectable.