Please fix tools like's been too long now!



I keep forgetting how much tools (involving meshes) are still seriously broken.
For many years these have been broken. It’s 2014 now and splitting a planar mesh should be working.

Today I need to split off a lot of strips from planar meshes…Rhino just cannot handle this in any way!
I’m stuck and need to go though hoops to perform a simple task like that.

Please take your users and your software serious and fix this type of malfunctioning.
It’s 2014 (mesh)tools offered should work more than just half of the time.

Here is a simple example of a mesh not being split by a line:
SpliMeshWithCurve.3dm (179.8 KB)

EDIT: I just made this example file and found it’s even worse: the result is … well see for yourself:


Invest in fixing these longstanding issues with obviously broken tools.

If I were in the position to choose a 3D-modeling tool without prior knowledge about Rhino, and ran into this type of alpha-quality tools for Meshes (not NURBS but straight forward Polygon Meshes). I would feel not much confidence in the software. I’d suspect if a company dares to ship software with tools this broken they must fall short in other areas too.

In 2014 a modeling package should be able to handle Meshes correct for all simple operations it offers.
Either fix these broken tools or be honest to us, to yourself and admit you are not up to offering this type of functionality and remove them from Rhino.
On the What’s new in V6 page, have a list of tools that have been removed to make Rhino more reliable.

Let’s be honest, the current state of many (mesh) tools is laughable.


Thanks for reading

I got this to work by not using SplitMeshWithCurve but just MeshSplit then the split seems correct.

MeshSplit is also broken…MeshSplitFail.3dm (109.9 KB)

I git this to work by Extruding the (poly)curves and using the Extrusions to split the Meshes
BE AWARE when doing this with curved surfaces:
For splitting this way, the rendermesh is used, not the Nurbs surface.


NOTE: this is a workaround with sacrificing the precision of the “straight line” curve!

It works but you have to make the curve at least 2 degree (‘Deg’ button in Curve tools pannel or ‘ChangeDegree’ command). Then you slightly and subtle move at least one of the CVs (those points of the curve are visible when you select the curve then use hotkey F10) or the start or end of the curve… to make it somehow slightly curvy.

Then the command SliptMeshWithCurve is working fine. :slight_smile:

P.S. The command MeshSplit works correctly for me with a poliline, line, arcs… whatever as a cutting tool you just have to refine the Mesh and Screen fraction form Rhino Options → View… :slight_smile:

Hi Ivaylo,

Thanks for the workaround. Unfortunately this is production critical and I need it to be as precise as I’m used to from Rhino.


Hey, Willem… another precise (this time) workaround.

Simply project (command Project) the straight line onto the mesh… then it is ON the mesh and works with the projected line which in our case here is also a straight 1 degree line!!!
I know it appears to be pointless because the inital line and the mesh are considered to be on the same plane… but anyways, I am offering the precise solution.


P. S. I should admit that the SplitMeshWithCurve command is somehow broken = works wrongly.

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All the mesh tools are a source of serious frustration in Rhino. I don’t even attempt to use them anymore.

+1 for McNeel devoting resources to mesh tools.

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Especially with the massive influx of cheap 3d scanners coming to market lately. If McNeel doesn’t work on this then they are going to be seriously left behind