23 Replies Latest reply on Nov 10, 2008 5:51 AM by Kevin De Smet

    centering a circle on a square?

    Ali Abdul
      Hello,
      How could I us relations to center this circle on the extruded box face ? in other words, is there another way to center the circle without using dims?

      Thanks in advance.
      Ali
        • centering a circle on a square?
          Bill Reuss
          Draw a construction line from corner to corner. Add a midpoint relationship for the center of the circle to the construction line.
            • centering a circle on a square?
              Ali Abdul
              ya i guess that woudl do it, but its almost more steps than just adding dims. i was thinking if there is such a feature/relation to just tell it to center itself between edges or something.
              thanks,
                • centering a circle on a square?
                  Depending what you are doing you could use a center rectangle in the sketch to create the box then make the circle coincident the the center point.

                  Or use a center rectangle and put the origin in the center of the box, then you can base the circle off the origin.
                  • centering a circle on a square?
                    Alan Stoldt

                    Ali A wrote:

                     

                    ya i guess that woudl do it, but its almost more steps than just adding dims. i was thinking if there is such a feature/relation to just tell it to center itself between edges or something.

                    thanks,

                    One benefit from doing it this way instead of dimensioning is that it is parametric. If for whatever reason your square sizes change, the hole is always centered. If your square becomes a rectangle, the hole is still centered.

                    If you define the hole center with dims from the edge, that is where it stays, relative to those edges.

                    Just a thought.
                • centering a circle on a square?
                  Troy Peterson
                  There are several way to do this.

                  Add a construction line diagonally to the square and constrain the center of the circle to the midpoint of the construction line.

                  Constrain the center of the circle to the midpoints of the square using horizontal and vertical.

                  Draw two construction lines from the midpoints of two of the sides of the square till they meet in the center then constrain the center of the circle to the intersection of the two construction lines.

                  *Edit - If you created the square where the origin is the center of the squre you could just constrain the center of the circle to the origin - one constraint.
                    • centering a circle on a square?
                      Ali Abdul
                      "Constrain the center of the circle to the midpoints of the square using horizontal and vertical. "

                      Troy, how coudl I do that? if i highlight teh circle and anyone of the square edges it only shows me a tangental relation.
                      Thanks,
                        • centering a circle on a square?
                          Brian Lindahl
                          RMB on a vertical edge of the square and "Select Midpoint", then CTRL-click on the sketch circle center point. Make the two points "Horizontal". Repeat with the midpoint of a Horizontal edge and the circle center point, and make vertical. No construction lines required.
                          • centering a circle on a square?
                            Troy Peterson

                            Ali A wrote:

                             

                            "Constrain the center of the circle to the midpoints of the square using horizontal and vertical. "



                            Troy, how coudl I do that? if i highlight teh circle and anyone of the square edges it only shows me a tangental relation.

                            Thanks,

                            Attachment has two of the simplest ways to constrain circle. Also see image to answer the question above.
                              • centering a circle on a square?
                                Ali Abdul
                                guys thanks for all of ur comments.


                                troy,
                                I just cann;t see the vertical and horizontal relations. I highligh both the circle and the edge (sometimes i pick the circle from teh origin and sometimes from its edge) and i still cann;t see those two relations. i must be doing something wrong.

                                Thanks,
                                  • centering a circle on a square?
                                    Ali Abdul
                                    troy,
                                    nevermind i think i coudln;t see them because the origin of my square/box is not in the center, but its off to one of teh corners.
                                    Thanks
                                    • centering a circle on a square?
                                      Dwight Livingston

                                      Ali A wrote:

                                       

                                      guys thanks for all of ur comments.

                                      troy,

                                      I just cann;t see the vertical and horizontal relations. I highligh both the circle and the edge (sometimes i pick the circle from teh origin and sometimes from its edge) and i still cann;t see those two relations. i must be doing something wrong.

                                      Thanks,

                                      Don't pick the edge; pick the midpoint of the edge. Don't pick the circle; pick the center of the circle. Once you have these two POINTS selected, you may choose a horizontal or vertical relation.

                                        • centering a circle on a square?
                                          Kevin De Smet

                                          Dwight Livingston wrote:

                                           

                                          Don't pick the edge; pick the midpoint of the edge. Don't pick the circle; pick the center of the circle. Once you have these two POINTS selected, you may choose a horizontal or vertical relation.

                                          I can't replicate this either I'm afraid. I even filter for midpoints and sketch points/segments and the filters even behave awkward doing that - 2008 SP2 build.

                                          Anyway - as an added possibility, you can create a Reference Geometry -> Point, which has the option "Center of Face". Particularly useful for extravagant shapes whose center is not easily determined by a simple construction line or two.
                                            • centering a circle on a square?
                                              Devi Prasad Samal
                                              Hi all,

                                              May be the best way or fastest way to place a circle at the centre point of a rectangle plate is

                                              click the centre point of circle then drag it to the one edge of the rectangle, it will show the mid point of the edge ... then drag the circle point to that mid point of edge and mid point relation(of auto snap option) will appear,

                                              then drag the circle perpendicular to the edge and then go to second edge and do as above.

                                              now move the point to the middle automatically 2 refference line from the edges appear which merge at a point and that will be the centre point of rectangle.

                                              please see the jpeg images for better understanding.

                                    • centering a circle on a square?
                                      Matt McKendrick
                                      If you face is truly a square, then you could use the polygon sketch feature. Open the sketch on the face of the square, select sketch entities>polygon, select number of faces = 4, select inscribed circle, then place the polygon (square) somewhere, it doesn't matter on the size and position at this point. Then select an edge of your square face and an line from the square sketch, and add the relations, equal and colinear. Repeat for an adjacent edge, and viola...., you have a circle inscribed in the square. All you have to do now is convert the square sketch to construction lines and the inscribed circle to regular lines.
                                    • centering a circle on a square?
                                      Kelvin Lamport
                                      Pilun ... you mirrored my thoughts exactly.

                                      Ali ... you do not have to actually apply a constraint. After drawing the diagonal, simply start drawing the circle by placing its centre at the midpoint of the diagonal.
                                      • centering a circle on a square?
                                        Kevin De Smet
                                        The method of relationing to the mid-point is quite tricky. You can't filter midpoints - click midpoint - (optionally) turn filter off - click circle centre. It only allows "Fix".

                                        You can do it, however, by right-clicking the edge and from the menu "Select midpoint" and then clicking the circle centre - horizontal or vertical and even coincident join fix in the possible relationships. Cool!
                                        • centering a circle on a square?
                                          Roland Schwarz
                                          Regardless of which method one uses to geometrically center a circle, none is "too much work". If one finds drawing and constraining a few construction lines is too hard or time consuming, then one ought to consider putting effort into refining one's sketch skills. Sketchin is THE core skill that can make or break a new SW user.

                                          My personal preference is to center using the intersection of two centerlines constrained symmetric to the sides of the square. This method is most robust, and would withstand the most variation in geometry and still hold the geometric center of the four-sided shape.
                                          • centering a circle on a square?
                                            Kelvin Lamport
                                            Kevin,
                                            Do you have the Automatic Relations and Snapping functions enabled?