Difficulty creating a single double sided component using Transform Mirror with Connect to Existing Points selected

[Simon Watt]

While I’ve had Delftship Pro for a couple of years, my experience is limited. I’ve searched the forum and not found or recognised any relevant topics for my problem.

A little background on my project.
I have used DP to create a streamline shell for a recumbent bicycle. Real size is 2.7m long, 0.617m wide and 0.72m deep. It is formed as a symmetrical model. The chines creating the multiple strakes of the “hull” were imported from airfoil coordinates. All of this has been a learning process and I’ve been pretty happy with the results. I’m about ready to have templates of each of the strakes printed full size from the Plan Developments. This has worked perfectly well.

My difficulty.
Because of material sizes, I’ve decided I want to have developments of both sides of a plank/strake, around the nose for instance, as a single piece. To do this I turned off the symmetrical option in the Layers dialog, and then used Transform Mirror with Connect to Existing Points selected. For several of my planks this worked as expected and I’m very happy. However, several others, which are similar and as far as I can tell have the same properties, are not connecting properly. The result is instead of the two points of the shared edge being connected and a common edge created, only one point is being connected. This leaves two boundary edges in the middle of my plank, joined at a common point. I have checked that my edge is on zero Y coordinates for a Vertical mirror join.

I imagine the problem is deeper in my model, but just wondered whether anyone with more experience might recognise this problem and give me some pointers.

Sorry for the long blurb
Thanks for listening and any help you can offer. Happy to upload my file if anyone had the time to look.

Cheers, Simon

[Marven]

Dear Simon,

I’m not really sure why this happens (or even if I fully understand your problem). It would be helpful to have your model to check what happens. If you don’t want to share it with the rest of the forum send it to info@delftship.net.

One more thing, why did you mirror your model? Setting the symmetric property of the corresponding layer should automatically create a duplicate and mirrored development of your surface. Or do you want to cut both sides as one single peace of material?

[Icare]

Are you sure that the line you call an “edge” is really an edge of your model?

May be it’s just the edge between two polygons (each one on a different layer) and only one being shown (the other being on a hidden layer).

[Simon Watt]

Well as far as I know it’s an edge. It selects when I click on it. It displays normally. It’s a crease edge or boundary. I think it’s an edge. It’s not shared or common with any other components that I’m aware of. How would I check for it having a shared point or edge with another component, or being in a hidden layer? This sounds possible, as I am a bit of a novice.

[Simon Watt]

Eureka!
I have the result I wanted.
I remembered that I had moved the whole model 100mm vertically, before I attempted to mirror planks.
I deleted the offending planks from the model.
I reimported the planks at their original created height.
I was able to mirror the planks as expected. Then I moved each plank vertically to match the rest of the model.

The difference is in the fine point dimensions. The outcome doing it this way appears to indicate that the edge delineating points differ in the X dimension by one ten thousandth of a millimeter – that would appear to be the problem. This point location discrepancy was not apparent when I inspected the points before and after the mirror function.

Thanks for all your help and suggestions, I appear to have fumbled my way through – for now:)

[Simon Watt]

That should be “ten thousandth of a meter” NOT millimeter !

[Author]

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