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Covert to spline command in Sketcher

Alexandrite

Covert to spline command in Sketcher

Hi, I just realized there is this "convert to spline" in sketcher  but I failed to locate any document about this command. Anyone can help ? Thanks.

convert.jpg

4 REPLIES 4
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Re: Covert to spline command in Sketcher

I don't think this will help you but this functionality has been in sketcher for as longer as i can remember & that is a long time. I started using the software back in 1996 (Pro-enginner V16). Pretty sure it was there then.

 

John

Re: Covert to spline command in Sketcher

Convert to spline within sketcher will overlay a best fit spline curve on top of one or more sketch entities. If more than one entity is selected then they must all have a minimum of G0 (position) continuity, i.e. multiple entities must be connected without gaps between them. Selected entities should form a single continuous chain. In practice I  can not recall using without a tangent connection between the entities.

 

A new sketch entity is created (spline) while retaining the underlying geometry used to compute the spline. Once you perform the conversion you can confirm this with query select where you will see the spline and the underlying geometry available for selection.

 

This is useful when you need curvature continuous curves.

Re: Covert to spline command in Sketcher

Thanks. This works exactly the came as "copy curve/approx" and I am interested to know if the both end points of the newly generated curve(spline) :

 

1. remain at the same locations (as old/referenced geometries)

2. have the same tangent. The tangent at connection points are definitely different as the new curve needs to achieve g2 continuity.

 

Re: Covert to spline command in Sketcher

The start end end points should be the same as the underlying constructs. I am not certain about the tangent vectors, I am thinking that they may not always be maintained due to math constraints.

 

If you need control if the tangent vectors direction you could create additional constraints on the underlying sketch geometry for tangency, I am thinking additional entities that are connected to but not included in the curves converted to spline. Think drawing the tangent vector direction and applying G1 constraint for adjacent curve.

 

See the enclosed pic & model. The red is the spline created in sketch 4, the indicated tails were used in the sketch to control the tangent vector angle. Features 13-14 are measures of the tangent angle of the spline conversion used to check against the tangent angles defined in sketch 4. They do match in this case.

 

If you need to control both direction and magnitude of the tangent vectors then you should look at ISDX curves.