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How to draw an omega shape

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Message 1 of 6
Anonymous
1700 Views, 5 Replies

How to draw an omega shape

Anonymous
Not applicable

Hi everyone, 

I want to draw an omega shape like the picture that I am attaching. I want to use one line such as a curve to draw this instead of rectangles and circles because my main concern is to import this AUTOCAD file to COMSOL multiphysics and have it as a closed-loop (such as a parametric surface and parametric curve). Please, any help is very much appreciated. Thank you.

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How to draw an omega shape

Hi everyone, 

I want to draw an omega shape like the picture that I am attaching. I want to use one line such as a curve to draw this instead of rectangles and circles because my main concern is to import this AUTOCAD file to COMSOL multiphysics and have it as a closed-loop (such as a parametric surface and parametric curve). Please, any help is very much appreciated. Thank you.

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Message 2 of 6
pendean
in reply to: Anonymous

pendean
Community Legend
Community Legend
1) two short lines.
2) a broken circle.
3) have all the ends touch, then PEDIT > Multiple, select all the objects, then JOIN them into one shape.

Try it: trace over your shape to keep the proportions.
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1) two short lines.
2) a broken circle.
3) have all the ends touch, then PEDIT > Multiple, select all the objects, then JOIN them into one shape.

Try it: trace over your shape to keep the proportions.
Message 3 of 6
Kent1Cooper
in reply to: Anonymous

Kent1Cooper
Consultant
Consultant

How important is the actual  shape?  The "circular" part of it is not really circular, so [for example] a Polyline with line segments at both ends and an arc segment between them, and with width, can't duplicate that shape very accurately.  And it wouldn't be able to do the intersections of the line and arc segments the way they're shown.  Here, the left one has a single arc segment making the curve, and the right one has three tangent arc segments.  Closer, but still not the right configuration at the "knees."

Omega1.PNG

 

But here, on the left is MTEXT in which I used an Omega character [slightly different shape from yours, but if you have the font you used...] in the chart called up by the Symbol option in the Text-editing ribbon, and made it Bold.  TXTEXP produced the two-outlines version in the middle, then a TRIM command removed the coinciding horizontals at the joint between outlines, and JOIN made it all into one Polyline outline on the right.

Omega2.PNG

 

Kent Cooper, AIA

How important is the actual  shape?  The "circular" part of it is not really circular, so [for example] a Polyline with line segments at both ends and an arc segment between them, and with width, can't duplicate that shape very accurately.  And it wouldn't be able to do the intersections of the line and arc segments the way they're shown.  Here, the left one has a single arc segment making the curve, and the right one has three tangent arc segments.  Closer, but still not the right configuration at the "knees."

Omega1.PNG

 

But here, on the left is MTEXT in which I used an Omega character [slightly different shape from yours, but if you have the font you used...] in the chart called up by the Symbol option in the Text-editing ribbon, and made it Bold.  TXTEXP produced the two-outlines version in the middle, then a TRIM command removed the coinciding horizontals at the joint between outlines, and JOIN made it all into one Polyline outline on the right.

Omega2.PNG

 

Kent Cooper, AIA
Message 4 of 6
ennujozlagam
in reply to: Anonymous

ennujozlagam
Mentor
Mentor

another way is to type character map in your search window look for the symbol and copy and paste it in your autocad drawing, if necessary you can explode and scale to suit your needs. thanks

 

omega.JPG





Remember : without the difficult times in your LIFE, you wouldn't be who you are today. Be grateful for the good and the bad. ANGER doesn't solve anything. It builds nothing, but it can destroy everything...
Please mark this response as "Accept as Solution" if it answers your question. Kudos gladly accepted.
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another way is to type character map in your search window look for the symbol and copy and paste it in your autocad drawing, if necessary you can explode and scale to suit your needs. thanks

 

omega.JPG





Remember : without the difficult times in your LIFE, you wouldn't be who you are today. Be grateful for the good and the bad. ANGER doesn't solve anything. It builds nothing, but it can destroy everything...
Please mark this response as "Accept as Solution" if it answers your question. Kudos gladly accepted.
Message 5 of 6
Kent1Cooper
in reply to: Kent1Cooper

Kent1Cooper
Consultant
Consultant

@Kent1Cooper wrote:

....  TXTEXP produced the two-outlines version in the middle, then a TRIM command removed the coinciding horizontals at the joint between outlines, and JOIN made it all into one Polyline outline on the right.


I don't know anything about COMSOL, so maybe this doesn't matter, but the result of that procedure is a Polyline using short line segments to make the "curved" parts.  If it needs to have real curvature, it can be made into a Spline instead.  Break it at the joints between straight and curved parts, use PEDIT to apply Spline curvature to the curved parts, then use SPLINEDIT to Join them all together [the straight parts will remain straight, even though part of a Spline].

Kent Cooper, AIA
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@Kent1Cooper wrote:

....  TXTEXP produced the two-outlines version in the middle, then a TRIM command removed the coinciding horizontals at the joint between outlines, and JOIN made it all into one Polyline outline on the right.


I don't know anything about COMSOL, so maybe this doesn't matter, but the result of that procedure is a Polyline using short line segments to make the "curved" parts.  If it needs to have real curvature, it can be made into a Spline instead.  Break it at the joints between straight and curved parts, use PEDIT to apply Spline curvature to the curved parts, then use SPLINEDIT to Join them all together [the straight parts will remain straight, even though part of a Spline].

Kent Cooper, AIA
Message 6 of 6
leeminardi
in reply to: Anonymous

leeminardi
Mentor
Mentor

Since COSMOL can work with NURBS splines as noted here,  I would create the shape with splines rather than a polyline with a lot of short segments.

 

I would start by creating a few reference lines for the vertical line of symmetry, and horizontal lines at the top of the two curves to be used to define the horizontal slope of the spline at those points.   Use a polyline for the straight segments (green) and 4 or 5 fit points for the curves (cyan).  The fit points I used are the blue grips you see highlighted. Use the T (tangency) option for the end of the spline and use osnap nearest to ensure the slop is horizontal.  Do not worry at this stage that the spline does not perfectly match the desired shappe.

 

 

image.png

Now select the spline a zoom into the area that does not have a good match and in the properties box change the Method from Fit to Control Vertices and the spline will show its CV points. 

image.png

Click and drag a CV to get a better match.  Below I've moved the 2nd CV.

image.png 

Edit the spline CVs as necessary and then mirror the splines and polyline.  Keep in mind that you get smoother curves with as few CV's as possible but if you need more local control of the spline's shape feel free to add additional CV's with the splinedit command.   You should find that you can get a pretty good fit in a few minutes.  Finish by using splinedit to join all the splines and polylines into one spline.

lee.minardi
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Since COSMOL can work with NURBS splines as noted here,  I would create the shape with splines rather than a polyline with a lot of short segments.

 

I would start by creating a few reference lines for the vertical line of symmetry, and horizontal lines at the top of the two curves to be used to define the horizontal slope of the spline at those points.   Use a polyline for the straight segments (green) and 4 or 5 fit points for the curves (cyan).  The fit points I used are the blue grips you see highlighted. Use the T (tangency) option for the end of the spline and use osnap nearest to ensure the slop is horizontal.  Do not worry at this stage that the spline does not perfectly match the desired shappe.

 

 

image.png

Now select the spline a zoom into the area that does not have a good match and in the properties box change the Method from Fit to Control Vertices and the spline will show its CV points. 

image.png

Click and drag a CV to get a better match.  Below I've moved the 2nd CV.

image.png 

Edit the spline CVs as necessary and then mirror the splines and polyline.  Keep in mind that you get smoother curves with as few CV's as possible but if you need more local control of the spline's shape feel free to add additional CV's with the splinedit command.   You should find that you can get a pretty good fit in a few minutes.  Finish by using splinedit to join all the splines and polylines into one spline.

lee.minardi

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