joining IGES surface in RHINO

[kazi_name03]

hello dears,
i have facing some problem when i want to join 2 or more surafecs in rhino. Sometimes the graphics shows that the surface are joined in rhino.But when i open them in maxsurf or shipConstructor in IGES format they are not in joined form? HOw i can join them in rhino for get a single surface? plese let me know asap. Thank u all.
Kazi Ashikuuzaman

[bhnautika]

Kazi name03 The join command in rhino is a bit misleading in that the surfaces don’t become one surface and in fact have to be exploded back into two surfaces in order to edited, its more like a group command. This is why programmes like Maxsurf see them as separate surfaces, even in maxsurf the combine command requires that each surface has the same number control points and stiffness to work. Rhino does have a command which may help “merge surfaces” but be careful as this can alter the area around the original join depending on the surface types being joined as rhino adds control points so both surfaces match.

[ACuttle]

Hello Kazi,
Bhnautika is correct and join in Rhino doesn't actually mathemically link the Nurbs surfaces so when other programs view them you will get errors or split surfaces.

The method I use to avoid this problem is to section both the surfaces I wish to join and then re-loft them into a single surface. Once you have the new suface you can run a few test sections through it and the original and check the deviations between the curves.

I don't normally find any problems doing this for any hull surfaces, though this method only works for surfaces where the joining point is parrallel to the direction of the section and the surfaces are planar (or close to) at the join. If they aren't you will have problems but depending on what you are doing you might not want to join these surface types.

[DCockey]

The MergeSrf command can be used to form one surface from two untrimmed surfaces provided the surfaces have a common edge or close to a common edge. Make sure you understand the options. The surfaces will be altered if needed to close any small gaps, and if Smooth=Yes they will be altered so the resulting surface is smooth. The Roundness value controls how far the alterations will spread.

[kazi_name03]

Thanks to all of my seniors and brothers for your valuable and effective suggestion.I was in holiday for few days and for that i cant reply here.Sory for that. I m trying to use the merge option. Some of the surface has joined with your suggestion but some of them are remained same. There is a display like, "Edges are too far" when i m trying to merge them but it seems they are very close. Is there any option in rhino to create mesh surface from iges or 3dm. I can make meshes from iges but cant make surface from that mesh. What can i do sir in this regard?

[ACuttle]

Re-lofting the surfaces from curves will avoid that problem but you could also tweak the surfaces closed with a fair few of the rhino commands - the best one to use might be quite subjective. You could run analyse>analyse curve deviation on the edges to be joined to see where your problems might be coming from.

[bhnautika]

Kazi_name03 this also could help you out. Use the “blend surface “ command to add a third surface between the two, you can adjust the way it connects by using the sliders in the control box. Now you can use the “merge surfaces” to combine them into one.