Unable to use "Offset Entities" on Splines and "Curve through free points"
Unable to use "Offset Entities" on Splines and "Curve through free points"
(OP)
Dear Fellas
I seem unable to use the “Offset Entities”- tool (in sketch mode) on:
* Spline
* Curves created by importing a set of coordinates (in a .txt-file) via “Curve through free points…” (under “Curve” under “Insert”) and then using the “Convert Entities” to get them onto the actual sketch plane.
Using the offset tool on a “line”, a “rectangle” or a “circle” for example is no problem. I am using the 2003-version of SolidWorks. Is this the reason, that earlier versions have a limitation here? Surely it works for todays versions!? Now I solve it by simply extrude the part and “shell it” however I am quite crippled by this limitation.
I seem unable to use the “Offset Entities”- tool (in sketch mode) on:
* Spline
* Curves created by importing a set of coordinates (in a .txt-file) via “Curve through free points…” (under “Curve” under “Insert”) and then using the “Convert Entities” to get them onto the actual sketch plane.
Using the offset tool on a “line”, a “rectangle” or a “circle” for example is no problem. I am using the 2003-version of SolidWorks. Is this the reason, that earlier versions have a limitation here? Surely it works for todays versions!? Now I solve it by simply extrude the part and “shell it” however I am quite crippled by this limitation.






RE: Unable to use "Offset Entities" on Splines and "Curve through free points"
Can you post a sample sketch to test on other computers?
RE: Unable to use "Offset Entities" on Splines and "Curve through free points"
RE: Unable to use "Offset Entities" on Splines and "Curve through free points"
So… success came when making the spline (or curve through free points) on one plane (the second plane), creating a new parallell plane (the third plane), marking the curve on the second plane (while being in sketch mode on the third plane) and do “Offset Entities” right away without first doing “Converting entities”!
When I try doing “Convert Entities” first and then do “Offset Entities” “within the same plane (third plane)” so to speak, it does not work! My that’s what you, TheTick, meant that I should do!?
So sample sketch contain:
Right: Curve through free points
Plane 1: “Convert Entities” on “Curve through free points” from the right plane. And clockwise after this comes: “line”, “3 Pt Arc”, “line”, “line”, “Tangent Arc”, and finaly a “Spline”. You can see that it offsets all but the “Convert Entities” on “Curve through free points” in the beginning of the “clockwise spiral” and the “spline” at the end
Plane 2: Success with “offset Entities” from marked curve in “plane 1” (Was this what you meant, TheTick?)
Plane 3: Doing convert entities on the curve in plane 1 and then doing the “Offset entities” on this, no success, no different result then in Plane 1.
RE: Unable to use "Offset Entities" on Splines and "Curve through free points"
RE: Unable to use "Offset Entities" on Splines and "Curve through free points"
I would guess that the same issue is involved in offsetting a non-sketch curve through points, and that solidworks sees those points similarly to inflection points on a spline. In your case it simplified into a spline with control points at the ends only, making it offset friendly.
I was able to get the double curvature spline to offset on Plane 2 by right-clicking the spline, and selecting "Split Entities" and breaking it into 3 distinct splines with endpoints at the inflection points.
I'll see if I can add a picture of my result.
RE: Unable to use "Offset Entities" on Splines and "Curve through free points"
Also the spline itself, the last (if going clockwise) part of the whole thing only had one inflectionpoint, If not counting the curve it was attached to.
I will attach the file and an image of this simples possible spline. Tell me if you can offset this one right away without any spacial treatment.
Did you say that you as well where unable to offset these curves before executing "split entities".
RE: Unable to use "Offset Entities" on Splines and "Curve through free points"
RE: Unable to use "Offset Entities" on Splines and "Curve through free points"
I experimented some more and was able to create and offset a spline with an arbitrary number of inflection points.
Also, I could offset your new file with no modification. If you cannot offset that one then there is something else at play here.
For the record I tested it in SW2011 and SW2013 with positive results.
After playing around the only real constraint I could find seems to be in the the resulting angle or radius of curvature that the offset would cause, ie. if curvature becomes too tight the offset fails. You can see from the pic of the first trial (attached this time) that my "solution" pretty much eliminated the curvature and tangency between the segments which is not really a solution if you are trying to maintain a smooth curve.
I suppose when I had run into problems with offsetting curves in the past I was attempting offsets that were large relative to the radius of curvature of the spline or curve I was working from, and just assumed that the problem was more general than it really is.
RE: Unable to use "Offset Entities" on Splines and "Curve through free points"
Thanks again for your input!