Offset a curve on a compound curve surface is there a command?

what command exists to offset a curve on a surface.

update…found it…OffsetCrvOnSrf !

OffsetSrf isnt of use.
Offset goes nuts on this attached file.
Need the border duplicated inwards 0.35inch.
Ideally hugging the surface, to then place a surface between the two., by using both curves to trim a cloned dome surface I reckon ! or is there another way to surface between the curves ?

Flaps V5 3D petals flowAlongCurve.3dm (2.6 MB)

A way to achieve an accurate offset:

Copy the domed surface in-place and work on the copy.
Split the copy with the petal outline - rotate the dome first to move the surface seam, otherwise you’ll have 2 split surfaces.
Offset the resulting petal as required, (Solid=no)
Duplicate the border the offset petal - this is your offset curve
Loft between the new curve and the curve on the split surface - OR choose Solid=Yes at the offset stage and delete unwanted parts

Steve, the above file has 38 Picture Frame bitmaps embedded. If I remember correctly, V5 passes on these embedded bitmaps during Copy Paste operations and may account for some of the slow down you’ve been experiencing - V7 lists the associated images as missing as you open the file and they can be cleaned out.


There is a test command for clearing these out in V5 ‘TestPurgeBitmapTable’ but take care as it will clear all of the bitmap table, you can always reload the ones you wish to keep. Type the whole word into the command line as test commands don’t auto complete.

Command ‘Audit3dmFile’ in the analyze menu will list the contents of the bitmap table

OffsetCrvOnSrf offsets a curve on a surface. Rhinoceros Help

OffsetNormal offsets a curve normal to a surface. Rhinoceros Help

Fin extrudes a surface normal to a surface. Rhinoceros Help

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I didnt realise rotating the dome to align seam was necessary,
I had done the offset curve on srf, cloned the dome, used the outer curve and and inner curve and trim leaving me with a .35 wide surface.
then used the inner curve and trim another dome clone and obtained the inner canvas area.
Then I did OffsetSrf solid=yes 0.1 outer beading, and 0.03 canvas area offsetting inwards (dome being outer extent, but then thought what the heck whats 0.015 beyond the limit and offset b=both instead !

Is there a hidden nasty in my method ? I guess I need to redo due that dome seam.

I had done so before this post appeared.

I also didnt know I was posting files with bitmap names all accessible. Thanks for the heads-up.
I will edit the file(s)


You can use SrfSeam to move the seam without rotating the object.

David thanks,
Is not doing seam rotation bad news, I must have not done it many times, never occurred to me.


I have run the TestPurgeBitmapTable and nothing happens, is it purged, how do I tell ?

where do I go to see ?

I also in the command line ran

I also ran Aufit3dmFilein the command line and a dialog box appeared but carefully reading it I could see no mentioon of the many bitmaps, and you say 'the analyze table, what and wher is this, I am V5.

is this not available to me.

I am getting folk seeing my imaged and names , something I didnt intend, and need to sort this out on past and future posts. WORRIED.

v5, how do I get rid of all bitmaps ?
If there is one I wish to have in the file then I will embed it.
How dare rhino display bitmaps when I didnt even feature them in the new file, and I used export selected to bring objects in to a brand new file, yet its just managed to do it againdespite no copy paste being used.