Joining two surfaces

excuse me for being new at Rhino, I am learning to make boat covers digitally and on this flybridge cover I forgot to measure one section at the back of the flybridge so have mirrored the cover from the opposite side.
Unfortunately I can’t seem to join the new panel to the main cover. It will need to bend into shape

I realise I may not have used the correct terminology but i’m learning.
fly - working copy.3dm (1015.4 KB)

The two surfaces have different structures. If the second surface was created using the Mirror command the surfaces would be identical. How did you create the second “mirrored” surface? Did you modify one surface?

The two surfaces overlap. If the surfaces are exact mirror images of each other you can Trim the surfaces to each other and Join into a single polysurface. If the surfaces are not mirror images of each other (as in you current file) then you may need to create an extended copy of one or both surfaces to use as the cutting objects.

this is where I fall down, i still struggle with the technical terminology but i’m getting there.

I only mirrored the thin section at the back and have been trying all sorts of tools to connect it to the main cover which I know is in the correct position… I thought Bend would do it but unfortunately not so I tried tools like blend but I don’t want to fill the gap I want to connect it as If I were sewing the parts together as I will be on the final product.

Probably best If I highlight the part that was mirrored.

I was confused by which surface had been mirrored.

The two surfaces do not have coinciding edges. Join requires each surface to be joined to have an edge which is coincident with the edge of another surface. You need to alter the surfaces so that edges coincide.

Most of your surfaces have a large number of control points which complicates revising the surfaces.

I assume you used the curves in your file to create the surfaces. It looks like your “centerline” curves are not quite on the centerline. So you might want to rebuild the original surface using a curve on the centerline. Then mirror that surface about the centerline and join.

entirely my fault with my request, and not really understanding what i’m doing :slight_smile:

I think I understand and I don’t’ have a problem with renewing my surfaces, unfortunately boats are rarely symmetrical and there will be an opening to go around a radar arch indicated by the curve in the center of the main surface in between the single points which are fasteners. I will see what I can do
If I had only take the measurements around that side of the radar arch it wouldn’t have been so difficult.

thank you for helping.

Hi @fragged8

I don’t have my Rhino with me at the moment, but judging from your screen grab, you might be looking for matchsrf (use the “position” option) to - literally - make ends meet. Matchsrf can pull the edge of the mirrored “sliver” to fit the edge of the main cover. The complexity of your surfaces might make the match look horrible, but it’s worth a try. Again, I’m not sure if that is what you are looking for, but hopefully :slight_smile:

HTH, Jakob

EDIT: Please note, that Matchsrf only works with untrimmed surfaces, so if the surface is trimmed, you are probably looking at manually point editing things in place instead.

I’m sitting here playing around and I will try that thank you, if it is as simple as it sounds :slight_smile: i will have to read up on the definitions of trimmed and untrimmed too.

Thank you

it worked well, but not the way I need it to. the result looked like a fillet between surfaces as the smaller surface did not move. But a useful tool to know about thank you

Hi @fragged8

Note that you need to select the edge to change - in this case the upper edge of the sliver - first and then the surface to match to - in this case the main cover - second. And then choose position rather than the default (which I think is tangency). But again: I’m don’t have access to Rhino right now, so I’m really just guessing :wink:

I previously tried MatchSrf on the file @fragged8 posted above. MatchSrf doesn’t work as one might expected because of the distance between control points on the surfaces compared to the size of the gap and the overlap. MatchSrf results in folded surfaces.

thank you guys I really appreciate your help. I have managed to do what I am after but I did it in a different way.

I deleted the mirror copy and offset the existing surface curve in the Y axis by 25mm then offset that curve in the -z axis by 100mm, that basically gave me what I hope is the line that I missed when measuring… this way I can just do a simple loft :slight_smile: it still needs a little trim up but I think it might work.

now to mess about building the last 2 side pieces…

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This is one I made the traditional way (same type of boat ), up until now I have made everything by hand.

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Very nice! Did you use some sort of 3D scanning / digitising equipment?

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Yes, i spent £25,000 on a Proliner 8 to digitise . I hope it is going to be worth it :slight_smile:
still learning

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I am not sure, but I think portable 3D scanning devices such as Artec Eva, Leo could be very handy for scanning outdoors. Have you tried any?
Just curious, if there is a probe in Proliner how you are able measure a boat in 360 without re positioning a measuring devise? How do you match coordinates then?

the proliner is a CMM machine that uses a probe on a wire so has some limitations, there are two or three options for measuring in hard to reach places and around corners but it is advised to leap the machine to another position when possible. A leap is really easy to do and if done right the deviation will be less than 1mm which for what I do is more than acceptable. the best thing about the Proliner is that not being a laser it is not effected by sunight and shiney surfaces.

We have previously tried laser and structured light scanners such as the Artec and none have worked in a brightly lit outdoor enviroment with shiny, reflective gel coat surfaces. The gelcoat is like a mirror, imagine taking a photo with flash against glass.


I was told by one of the guys at prodim they are working on a combination of probe and photogrammetry that will be interesting.

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