Curve Paths on Blades

[[To...]]

I'm trying to develop a curve path on a Free Form Surface that follows more parallel to the top surface than a planar path.

I was able to create a 3D curve along the top edge with vectors normal to the wall, then rotated the vectors 90°, then translated the points down but the surface tapers as it moves down and the points do no stay on the surface.

Is there a technique other than creating the path via single points?

This is a step model.

Screenshot 2021-09-21 145458.jpg

[[To...]]

UPDATE: I was able to use Offset in the Create window. The offset is metric and created a curve with 2 rows of points. I was able to delete the points I didn't want and ended up with exactly what I was looking for.

Screenshot 2021-09-21 151316.jpg

[[Cl...]]

So does the offset just move all the points inividually by the same amount.

[[To...]]

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Yes, I tried a 12mm offset to create a path mid-way down and besides the extra points that I was able to delete, it worked fine. I ran into a problem when I selected the bottom edge of the blade. On one side of the blade it worked ok, but on the other side there were no points... Back to the drawing board. I think I can live with a flat section plane on the mid and lower paths.

Screenshot 2021-09-21 154116.jpgScreenshot 2021-09-21 154153.jpg

[[To...]]

This is what the top and mid curves looked like "as created" before i deleted the extra points. It was pretty simple after I turned "show point numbers" on.

Screenshot 2021-09-21 154506.jpgScreenshot 2021-09-21 154603.jpg

[[To...]]

This is curve from section for lower part of blade.

Screenshot 2021-09-21 155456.jpgScreenshot 2021-09-21 155527.jpg

[[Ma...]]

I'll post something what i found as usefull.

When you create curve and modify somehow nominals, then curve is not same as model.
But when you just select curve element, you see on model thin purple line ( spline of curve ) - you can select this spline ( in hierarchy or just selecting by clicking and on 2nd page of creating elements you select: 3d curve / from curves / edit num of points and it will generate points on model face following this spline.

This is usefull when is changed some geometry on model.

I can provide some picture manual if is my explanation confusing.

[[To...]]

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Thanks. I am aware of the issue you speak of. I prefer to use the method you described but I needed to create a curve path away from the top edge so the offset option on 1st page gave me. My last post with the mid and lower curves were created using the section option under "Generate Path" under 3D curve on 2nd page.

[[Da...]]

Try using a Cylindrical section concentric to the axis of the impeller !! It will be correct to the model. Cly section is at the bottom of the section tab in creating features.

[[Ma...]]

I think they know that cylindrical cut is available. But for some reason they are not using it.

[[Da...]]

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Well, they are not the only people reading this thread.

[[To...]]

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Maybe you help me with the cylindrical section settings....

Screenshot 2021-09-22 115409.jpg

[[Da...]]

First we saw of the whole part... Is the surface between blades a radius ? If you can lay the section on its side you could get close.

[[To...]]

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Fair enough... 😃

For the curve near the top of the blade, I used the offset value and got a curve that was exactly parallel to the top. For the mid-curve and lower curve, tilted plane sections were created and worked well because the curvature was insignificant. I posted pictures of the finished curves.

[[Da...]]

I saw the previous posts. But does off setting still actually follow the surface? I remember having trouble with that in the past.

[[To...]]

Good question. So, I changed the number of decimal places of my system to 8.

Then, I selected a point on the curve and recorded the nominal position of X, Y and Z.

Next, I went into CAD > Create and typed in the values of the curve point and created a Space Point. (Point1)

From the results below, the point is not exactly in the same spot but is it close enough?
Left is the Curve point from the offset curve. Right is the space point

Working in INCH.

I'm going to test some areas with more curvature to see if the results are similar.

UPDATE: I created a new curve with a 20mm offset. (Point2) Results are not as close as 3mm offset but still may be close enough.

Screenshot 2021-09-22 130025.jpgScreenshot 2021-09-22 131130.jpg

[[Ma...]]

If i remember correctly Calypso 2019 have curve symmetry - if you create one curve from top and one from bottom it could create some curve in middle which could be used for generating new 3d curve.

What version you have?

[[To...]]

Calypso 2020 (v7.0)

Another test using a 22mm offset from top edge curve. X, Y and Z values are within .000004"

I think the Curve Offset is working well with this particular model, in this particular version of Calypso. I suppose this may not be true in every instance.

Screenshot 2021-09-22 132854.jpg

[[Da...]]

Wow ! Looks Good ! Good to know, Thanks

[[Cl...]]

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So you created a curve like a vertical picket fence, rotated the vectors out 90° and offset it in Z?

Trying to picture this in my head.

[[To...]]

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Look at my 2nd post for reference.

I went to CAD > Create. I turned the shading off and selected the top edge of the blade. This creates the path of the curve.

Next, I turned the shading back on, held down the CTRL key (selecting mode) and clicked on the surface of the blade. This creates the surface vector.

Next, I changed the 100 points to 500 or so. Edited the offset value to 3, then clicked on the 3d Curve button.

[[Cl...]]

Got it, thanks Tom.

[[Lu...]]

Hello,
when i will to measure all blades on the wheel, is the best alignment 3D Best fit method? (Plane/circle/point on the one blade?)

Thank you so much for help
Lukas