# Interlocking brep assembly on arch

I am trying to rotate a brep according to the angles between each vector on a catenary arch.
comb model 2.gh (51.5 KB)
Right now the model looks like this:

But I would like for it to look more this:

@Samantha_Garza1, try editing your topic so you add the kangaroo category in order to get more adequate help - I sense your method needs some tweaking in terms of simulating an object of this type - based on your picture and looking at your model I suppose youâre aware of the discrepancies - though you can change the rotation of breps, the connection/notches wonât really align as breps overlap and intersect each other. Does this matter? Are you just after the âlookâ of it or actually trying to digitally fabricate/simulate this?

This is interesting.

So without changing too much and using the catenary approach it could look like this:

Please note some small changes in the definition:

The straight line connecting start and end point is divided by the number of segments you want to have. This results in x+1 of the cross shaped objects.

I set the line length to 0.5 units. That represents the distance your object needs to be moved so it interlocks with the adjacent Xâs. I moved your object so that the base of the slit is on the YZ plane. This way is can be oriented more easily on the final perp planes.

The inner group of the oriented objects collide and unless the slits are large enough, the assembly wonât behave like an inverted chain. I think the assembly bends in a different way and the catenary arch is not the right approach.

A more accurate simulation can be achieved by using a Rod goal instead.

Ask @DanielPiker why, but I think the regular solver works better than the bouncy solver for this simulation.

Youâll discover that increasing the Bend Strength of the Rod goal moves the end points outwards.

By adding a certain percentage to the target length of the polyline segments, you can make the Xâs overlap less.

I think Iâd try avoid using Rigid Body collsions in this caseâŠ

comb_model_rod.gh (59.3 KB)

PS: I recategorized the topic and changed your topic title. I hope thatâs ok?

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Thatâs a classic Plane To Plane Trans puzzle. You can âapproximateâ an indicative solution without K2 (meaning very fast solutions IF the N is big - unlikely âŠ but anyway).

Plus your X brep is not Parametric (so spot the Fixed pts used).

See attached (not a guide for you since itâs pure code âŠ so used it just for fun). For simplitity works IF the path is planar AND the path Plane is parallel to Plane.WorldXZ.

Brep_PtoP_Transform_V1.gh (147.5 KB)

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