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02-18-2018 09:33 AM

I try to create Bridge Curve between two non-coplanar curves.

I want to **adjust the tangent magnitude (left) to the maximum with the bridge still staying above the datum plane. **I find it very difficult to handle if Studio Spline is used to do the job. And my last resort is Combined Projection, which requires two sketches to be created first and therefore is very time-consuming.

Is there any better way to do the job? Thanks!

Solved! Go to Solution.

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10 REPLIES 10

Re: Bridge Curve in 3d

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02-18-2018 02:44 AM

Hi,

Can you use a G1 continuity rather than a G2 continuity ? Then you can manage your Tangent Magnitude within a bigger range (while keeping the bridge curve above the datum plane). In my opinion assigning a G2 continuity w.r.t the straight line does not make much sense either (G1 should do the work).

Also the top curve needs some refinement

I used a fit curve (i admit this can be refined further.) and this is the result after using bridge

Best Regards

Kapil

Re: Bridge Curve in 3d

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02-19-2018 03:22 AM - edited 02-19-2018 03:24 AM

Hi @kapilsharma

Thanks for your suggestions!

Yes. I should simply use G1 with straight line.

And you suggested me to refine the curve, but in my real model it's an edge left by Trim Sheet. I know it's not good. In this situation, if I copy/refine the edge and then use the refined copy, I'm afraid the continuity within the model would be damaged. Any of your suggestion on this issue would be appreciated.

Back to the topic in my original post, I was seeking some way to reach the maximum tangent magnitute while keeping the bridge above the datum plane. Now it seems that I can only depend on my visual judgement to make sure the bridge staying above the datum plane. I wonder whether there is some reliable way (constraint?) to make sure the brige would stay above the datum plane during the process of dragging the tangent mangintude.

Re: Bridge Curve in 3d

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02-19-2018 03:32 AM - edited 02-19-2018 03:34 AM

Edge from Trim sheet ....I can understand that

It leaves you with little choice then. If possible you can use tangent continuity for the top (trim curve ) as well.

The moment you try to use G2...the bridge curve goes further down to accomodate that and hence although you get a nice curvature comb but it might leave some "inflexion" near the straight line. As a rough rule if you wish to maintain the curve above the datum plane more stringently then use a bigger tangent magnitude value for the straight line side also...else it should be checked visually only (or checking any inflexion point in the vicinity of the straight line-bridge curve interface.)

Best Regards

Kapil

Re: Bridge Curve in 3d

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02-19-2018 03:47 AM

Hi @kapilsharma Thanks for your comments!

Re: Bridge Curve in 3d

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02-19-2018 09:00 PM

Hi @surfactant

As I think, this trick can be helpful for your situation.

It can be made with connected 2 brdige curves as below.

1. **Project** the curve (left side) to Datum Plane of the line.

2. Create **Bridge Curve** with the **projected curve** and **line** (right side).

[co-Planar Bridge curve region]

3. Create **additional Bridge Curve** with** Bridge Curve **[step 2] and **original curve** (left side).

(You can specify contact position of Bridge Curve from Connectivity option.)

Re: Bridge Curve in 3d

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02-19-2018 10:35 PM

**"additional Bridge Curve"** with a half lying in the datum plane and the other half above the plane.

Re: Bridge Curve in 3d

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02-19-2018 11:54 PM

@surfactant wrote:"additional Bridge Curve"with a half lying in the datum plane and the other half above the plane.

Actually,

The 1st Bridge Curve lying on datum plane and another Bridge Curve above the plane.

The **"additional Bridge Curve" **just connect the 1st Bridge Curve to 3D curve.

Re: Bridge Curve in 3d

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02-19-2018 11:57 PM

Hi @SKAHN Thanks! Yes. I made a mistake. Your final bridge would be composed of two parts:

- 1st Bridge Curve (lying on datum plane)
- additional Bridge Curve (above the plane)

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02-20-2018 03:30 PM

Hi Surfactant,

Your requirement would be solved by adding a Curve Analyze to your bridge curve and use the Projection option – here I would use Datum Axis in the X-direction as input. You need to turn on the Inflection to show you when it appears (marked as a blue X where the curve start to change direction (below your required plane). You are most likely helped by turning on the Curvature Combs as they clearly show the change – not necessary but you do need the Inflection Point). By using the drag handles and study when the Inflection appears you can now easily determine your Max Tangent Magnitude – when no Inflection Point your curve is above the plane.

Have a look at the attached movie file for clarification.

I hope this helps you

Best regards

Fred

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