Suggestions for good mesh splitting software

Hi All,

As we all know, Rhino is not fabulous when dealing with splitting up meshes (and that’s putting it politely).

For most of my work, it’s not an issue as I model in nurbs. However I occasionally receive mesh files from clients which I then have to split up into panels.

Rhino is simply NOT an option for this.

Does anyone have experience with any software that is good at splitting meshes with curves. Maya or 3Dmax will do it, but that’s a lot of software for me to buy for just one function.

Thanks in advance, Steve

Have you checked Blender? … I believe it has this ability and it can work with open surfaces. Meshlab is limited to booleans with solids.

If it is of any comfort, we keep an internal list of defects we call “tech top ten”. These are the issues that cause users and by extension support techs, the most on-going pain.
This is just one of the ways we try to prioritize development.
The general poor state of the mesh tools in Rhino is on that list as has been for some time.

Do you have an idea on when these mesh tools will get some love? is it something planned for Rhino 6?

Sorry, I don’t.
It won’t be for the initial release of V6.
I don’t know if meshing can be improved in a service release or not, but that’s a possibility.
I do know that there is a lot of pressure internally to work on meshing and plenty of motivation to do so. Generally that means something is going to “get some love”, but there are a lot of other considerations to weigh and balance before resources are allocated and work begins.

Hi Steve,
I use max and I think Rhino is much better at splitting and dealing with meshes than max is.
It sounds like you want more than just splitting a mesh. I find Rhino works really well for splitting meshes. Maybe more detail and an example of what doesn’t work.
RM

The typical failure I have experienced occurs when the split lines up exactly over a mesh vertex. It seems like rhino cant decide what to do and fails as a result. Often moving the mesh or the split line slightly solves the issue however this is not always an acceptable work-around. Sometimes the cut needs to be exactly there or sometimes the mesh is so dense that a collision is inevitable. For specific examples see:





There are others but that is what a quick search of the forum turned up.

This error can also flow through to the mesh Boolean functions and cause them to fail as well.

Hi,
I’m not saying Rhino is perfect for mesh splitting I’m aware of the mesh failure posts, in Steve’s case it might be something fixable. I get some of these same errors in max so it’s not just a Rhino thing but I wouldn’t dream of trying to spilt large stl files in max and expect to export them for rapid prototyping as water tight solids. I find Rhino’s ability to heal meshes using the mesh repair tools a huge bonus that is only found in the most expensive software.
I too vote to get rid of those errors but that’s another post.

RM

Hi,

Well it’s good to know that Max struggles as well.
Wattzie included a few good examples so I won’t bother adding more.

I’m already pretty good at tweaking things to get an acceptable result in Rhino. It’s just that with a model where I might need to add over three hundred seams it can get pretty tedious fiddling around and having to carefully check that an orphan mesh hasn’t appeared for each and every seam.

I suppose I was just hoping that someone had come across software that deals with this easily and reliably.

Oh well, back to tweaking I guess :wink:

Thanks for input everyone. Steve

Hi Steve,
Actually that first example Wattzie posted is not a good example of the split error in Rhino there are major flaws in that mesh and failure at splitting is not a rhino bug in that case. It looks to me that two meshes or parts or them are welded together so there are major duplicate vertexes in the same spots. I was able to split the mesh in Rhino to some extant by exporting it out as obj format and importing it back in, but then you will see when you split it there is just bad topology which is what is messing up the split.
I tried it max 2016 and there are no results on it worth mentioning. Also in V6 this mesh won’t even display in rendered mode until I export it out as obj format then reimport it. Maybe Wattzie and you have to deal with these bad topology meshes? I haven’t tried it but I think one way around this is to open in 3d coat and use this as a base for a re-topology all quad mesh.
Also if one really needed to you could crtl shift and select polygons and delete them and then stich the edges back with the mesh face command but that’s a huge workaround.

I feel your pain, and it’s a drag because we all know Rhino’s the best at handling large projects, You might find some software that does this but managing 300 seams it might not do. I sure wouldn’t want to do 300 seams in max. Maybe try clothing/pattern software
RM

Hey RM,

Luckily it’s very rare that I have to deal with this sort of thing. I’m usually modelling in TSplines.

Re. Your suggestions.
Yes, I often use 3DCoats retopo to get nice meshes. It’s sensational for that (and of course for UVing and painting).
Clothing software I have a veeeeery expensive setup here for that sort of thing and it works pretty darn well.

Looks like I am not going to get anything better at the moment eh? Oh well :wink:

Thanks, Steve

Steve,
if you already use 3DCoat and know its UV workspace the solution should be near.
Simply slice up your irregular customer-supplied meshes with the UV-Path tool (it is optimized for Hi-Res meshes and can deal with far higher polycounts than shown in the video). Export out as obj, import to Rhino, explode. If you move individual patches to new UV-sets inside 3D Coat (which tidies up the view) you will not even have to explode.

The same thing works btw. when you assign polygroups, say in Zbrush via masking and then import to Rhino. Rhino can not deal with any sort of logical grouping in meshes and therefore splits them into patches – which is actually a bad shortcoming – but good for you.

Hifred,

Wow, perfect! I’ve been working with multiple UV sets in 3DCoat and your suggestion completes the picture. I never realised that UV seams created in 3DCoat actually split up the mesh.

Many thanks, Steve

Well, they don’t – at least inside any program that handles meshes properly.
Rhino fails – and that’s good for you :o)

Those who want to render meshes with multiple UV sets inside Rhino (with any
native or plugin renderer) will perceive the same thing as a bad limitation.

Holger

PS: Just for clarity: UV seams created in any other software will import in the same
way as geometry edited inside 3DCoat. The latter only has a shortest path based
UV-tool which works well for irregular meshes.