Offset issue

[dinocoglitore]

I found some behavior that I don’t understand regarding the offset of a set of closed loops.

I have two closed loops almost similar, generated by two dxf file and slightly rotated by an angle.

I used the same function to generate the offset inward for the two closed loops.

This is the code:

 

def offsetShape(sketch, thickness):
    try:
        app = adsk.core.Application.get()
        ui  = app.userInterface
        
	spline = sketch.sketchCurves.sketchFittedSplines.item(0)
        
        # Create a collection of entities for move
        curves = adsk.core.ObjectCollection.create()
        # move the entire oval
        curves.add(spline)

        # Create the offset.
        dirPoint = adsk.core.Point3D.create(0, 0, 0)
        offsetCurves = sketch.offset(curves, dirPoint, thickness)       
		
        # find the inside profile
        # item(0) should be the outside profile
        profInt = sketch.profiles.item(1)
		
        return profInt
		
    except:
        if ui:
            ui.messageBox('Failed:\n{}'.format(traceback.format_exc()))

I find the same behavior using the UI. So I recreate the issue using the interface.

If I create the offset for the first loop all is ok. It generates a closed loop inward:

It creates only one closed spline .

But if I do the same operation for the second loop it give me two splines (this could be right) but it does not close the loop:

 

Someone can help me ?

Thanks

Dino

[ekinsb]

It seems that the curves in the second place aren't connected.  They may or may not geometrically touch (the endpoints are at the same coordinate) but I don't think they share the same sketch point.  The white point that I can see in your image indicates that there is an free end point.  Because they're not connected, the offset doesn't attempt to keep that corner closed.

[dinocoglitore]

Hi Brian, thanks for the immediate reply. But there is something that I don’t understand in your answer.

When I use the offset operation I start from a closed loop that has no point on it.

It is closed, in fact I can select it and point out the relative profile.

When I use the offset operation on it,  a point (the white one) springs up on the original spline and the created curve (inward offset curve) is open and consists of two spline.

I can see the gap in the offset curve if I use the max zoom I can use in the UI.

With this zoom there is no gap in the original curve.

In addition I can remove the white point on the original curve, selecting it and deleting it.

Thanks

Dino

[dinocoglitore]

Just another little information.

The original curve come from a scale operation.

Is it useful to understand the issue ?

Thanks

[ekinsb]

It's best if you can provide a very small data set and a series of instructions that we can use to reproduce the problem.  If you can reproduce just using commands and not the API that's even better because then we know it's a general problem with the command functionality and not something that is API specific.  If I can reproduce the problem then we can investigate the cause and hopefully fix it.

[dinocoglitore]

I thank you for the reply. Maybe I’ve found the problem. It is connected to the copy operation from one sketch to another.

I attach three dxf file: 22.dxf, 21.dxf and 2.dxf

The first have no problem. The second and third have it.

These are the steps I followed to reproduce the issue.

·         Insert a dxf file choosing the XY plane (this create a closed curve – CURVE_0 and a new sketch – (it has the name of the dxf file)

·         Create a construction plane with offset 22.5 mm from the XY plane

·         Create a sketch (SKETCH1) over the new plane

·         Select the CURVE_0 and copy it on the new sketch (SKETCH1). I call it CURVE_1. I used CTRL-C – CTRL-V to make the copy.

·         Use the Offset operation selecting the CURVE_1 and choosing an offset of -1.0 mm

If I use the 22.dxf curve there is no problem. If I use the 21.dxf or the 2.dxf curve the problem arises. If I use the offset operation on the same sketch there is no problem at all.

Maybe the problem is connected to the dxf file ? I have no competence about the dxf format so reading the file with an editor I cannot understand if there are problems.

When I do the copy operation a white point arises in every dxf file. I don’t know why !

I hope that the description is clear.

 

Thanks a lot

[dinocoglitore]

Here are the dxf Files.

Thanks

Dino

[ekinsb · Accepted solution]

I've logged a bug for the sketch team to look at it.  Since it's a bit of an odd workflow I'm not sure how high of a priority it will be compared to other tasks they're working on.

[dinocoglitore]

I thank you for your kindness. If you think that the problem I had is a little bug, I hope that the problem will be solved soon for the sake of the community.

Dino

[dinocoglitore]

I Brian, I had the doubt that the problem can be connected to the DXF files that I sent you so I decided to recreate the two file 2.dxf and 21.dxf. I drew again the closed splines and I made again the tests. The result is that the problem has gone away.

Talking with you has been helpful and it has clarified the problem.

I thank you a lot

Dino