Add rectangle coincident with mesh

[Sean_Dzafovic]

I have created a 3D mesh from a terrain raster and a photo overlay. I want to create a rectangle the same dimensions as the model and then use the Extrude to Surface tool to make a base for the mesh/model in order to make a 3D print.

I’ve tried using the “Make surface from 3 or 4 points” tool to make a rectangle, but I am just eyeballing the corners and wondered if there was a more precise way to do it.

Extrude To Surfae

Download Link: Extrude To Surface v1.0 | Food4Rhino Extrude To Surface is a grasshopper component, created by me, that will allow the user to extrude 2D shapes to a boundary surface, where the top part of the extrusion takes the form of the boundary’s topology. Version 1.0 has three inputs, but the first 2 are the most important ones: 1- Taper: the user can taper the top part of the extrusion. The top part of the extrusion will maintain its topology taken from the boundary surface. 2- Offse…

[piac (Giulio Piacentino)]

Hey @Sean_Dzafovic

could you post a small piece of the surface, so I can give you some instructions?

Generally, if it’s already rectangular but on different heights, I’d use DupBorder or extrude the curve downwards, then FillMeshHole(s). Or some MeshSplit.

Giulio

[Sean_Dzafovic]

here is a screenshot of the mesh in Rhino. (I can post the Rhino8 file if required)

I did try DupBorder, but I get this (Image/terrain drape was done in ArcGIS Pro, which exports the model as multiple small tiles - 401 for this model)

Mersey_Subset.3dm (9.8 MB)

[René_Corella]

@Sean_Dzafovic your mesh has an odd orientation—perhaps intentionally. Anyway, since you already have the parcel boundaries, you could just Ctrl+Shift select contiguous border segments in bulk until you end up with the outer boundaries and join them:

For a bit less cleanup, you can also get there with:

1. SelMesh + Isolate + Join + DupBorder
2. Ctrl+Shift select curve segments touching border:
   
   
3. Delete anything left ‘inside’ and then join all curves into one:
   
   
4. If it says the curve is open you might have missed a super tiny segment so use CloseCrv and just for sanity run SelSelfIntersectingCrv to rule out a potential self intersection.

meshborder.3dm (100.5 KB)

[piac (Giulio Piacentino)]

Important: these are Rhino 8 instructions. We are working on making this simpler for RhinoBETA/Rhino 9

If you can print with Vertex Colors (most printes can) this will work quite well. Doing this takes a few steps but it’s very easy and requires no crazy manual work once you know how to do it.

This hopefully will be possible entirely with 0 manual work and the result can be still be a beautiful mesh. Here’s how I’ve modeled this:

• Select everything, and Rotate3D along the 0,0,0->1,0,0 axis by 90°. It’s easer to model on the XY plane in Rhino

• ComputeVertexColors on each piece. Most tedious bit, but do NOT forget any piece or your mesh will become white later. This command bakes the material into vertex colors, so we can join them

  

• SelCrv → Delete (so we can see better any problem)

• Delete all materials in the Materials editor

• Join all meshes together. If they become white, you likely forgot to compute colors for a piece

• AlignVertices → DistanceToAdjust=0.01 AverageVerticesToAdjust=Yes OnlyNakeds=No

• (MatchMeshEdge if more edges were still open at T-joints, but none persisted)

• Select the mesh, then UnifyMeshNormals

• ExtrudeCurve, then double-click the mesh exterior border. This will extrude the polyline into a list of polysurfaces. Then Mesh it with few polygons (detailed - no simplify, no refine, 0 density and rest all 0). SelSrf and DEL button. Then Join the sides. Do AlignVertices then Join top to the side (select, then run Join. Order matters).

• Draw a line, then run MeshSplit at the height you want. It can be fixed later.

• Join top and sides, take the top, and run FillMeshHoles

Closed, colored. See if you like it.

joined-subset-closed3.3dm (5.4 MB)