Unable to project block instances to surface

Having gone to the trouble of creating block instances and I thought they did project to surfaces, and placing them on Cplane using project Osnap when creating them, I now discover they wont project. :frowning:

If I select them in wireframe view Front then choose project it says select curves etc to project !

This is not the cause of the possible bug though in my other post…or is it ?

Now what do I do ? nuke them all I guess (explode)


Well, once you project them, they would theoretically not be block instances anymore anyway, so you may as well explode them first…


I was hoping to minimise memory and have the source circles which sit on Cplane at least as Blocks, knowing that the projected shapes would not be blocks.
Hundreds of circles were just one, but now they are also hundreds :frowning:

Why wont rhino let me project them ?

Projection doesnt alter the blocks, only their offspring which are not copies but new shapes so no reason to deny projection.


So you need to keep the originals and the copies…?

Block instances are not “real” geometry, just a stored transformation matrix of some real geometry somewhere. As such all sorts of normal Rhino commands/procedures will not be available for blocks.

I guess the thing to do in your case would be to select the blocks, explode, project the geometry, while the geometry is still selected, copy to clipboard, undo twice and paste…


I’m getting the feeling that you are doing things the hard way…
For me, this entire problem is shouting “Grasshopper” but I guess that’s not an option you are considering at the moment.

@rajaa asked you to provide an example file in one of your other threads. She is the expert on paneling around here. I really recommend you to answer her…

But perhaps you should also state where you are going with this. Is this purely visualization of an old aircraft? Are you making a 3D model from which plastic kits will be produced? Are you going the build the plane in 1:1?..

I will seek out the thread with rajaa. Any idea where it is ? panelling…sounds like rivet territory :slight_smile:

Its to provide dimensions to panel lines and rivets for creation of a full size aircraft replica.

Establish the usual plan type placement, always drawn in aviation world on an imaginary line down aircraft item centre, in our case we call it Cplane, with Cplane on aircraft datum.
Then the rivets are projected to port and stbd skins, giving the pattern and showing any non symetrical patterns of rivets and panels etc., so dims can be taken on skin and plotted on the replications skin, as its far easier working on skin with a tape measure !

Is Grasshopper better at working with engineering drawings and circles etc and drawing up aircraft ?
I google grasshopper rhino and see nothing that says cars ships aircraft etc. Wierd shapes and numbers with lines between.
Having declared I need to build aircraft from ancient engineering drawings as well as modelling items and been told Rhino would suit me, what would grasshopper enable me to do I cant do in Rhino. Google images grasshopper is stuff miles removed from my subject matter, some very wierd stuff there.


If your block is not changing and you simply need to orient it to your surface, then there are perhaps ways to do that. If you instead need to project the geometry to your surface, and if the surface, then the geometry will need to be altered and hence your block does not stay intact. Can you provide a small example (.3dm) to show what you are doing and what you need?

I will try to, Need to engineer some time first.