Hi

Would it be possible in the future to have the option to export the converted mesh file to 3dm rather than stl of obj. the Rhino viewer on the Ipad opens 3dm files which contain mesh and surface data. I would presume that the mesh data would be lighter on the ipad that the suface data?

3dcnc

The 3dm file would become too large with redundant information.

If you want to just look at the output on the IPad, just convert to a polygon format and use one of the apps that can read it.

Hi 3dcnc,

> Would it be possible in the future to have the option to
> export the converted mesh file to 3dm rather than stl of obj.

Maybe in the future, but I haven't yet figured out a way to do that well.

The problem is that just having a "Mesh 3DM" file listed in the regular file types for "Save As" could fairly easily lead to someone losing all their original data.

That could occur if someone thought they were saving all their actual surface data (since normally saving to 3DM format does that), but they were instead actually writing only mesh data to the 3DM file and no surfaces. The resulting "mesh 3DM" file would not even load back into MoI since it skips mesh objects in 3DM files.

So it could be pretty easy for someone to say - hey, where is my data? I just saved it to 3DM and closed everything down and now that 3DM file won't load...

That's a potentially really bad data-loss scenario that could be caused by adding in something that made 2 3DM formats show up in a file types list.

- Michael

And then with a different approach of trying to save both mesh and surface data within the same file (rather than having a special "Mesh 3DM" type export as I was describing above) has the problem that Steve mentions - file sizes would be greatly increased with information that's not actually used by MoI at all since it creates display meshes as needed dynamically when files are loaded.

Rhino has a method where it stores display mesh information in the 3DM file so that it doesn't have to recalculate it later, but the reason why it does this is because it has an extremely slow meshing mechanism.

Since MoI has a very fast meshing mechanism it eliminated the need to store all that large amount of display data in the file.

Some programs (like that iPad viewer for example, and some import plug-ins for some other programs) have started to read only that display mesh data out of 3DM files, but that's not a very good approach because that data is not even necessarily present in files that Rhino writes - it only will only be present from Rhino saved files if you've done a render in Rhino first before saving. It's basically a cache of some of Rhino's display information.

- Michael

Thanks . I agree. Its probably a bad idea. But I learnt some usefull information about the render mesh.

"it only will only be present from Rhino saved files if you've done a render in Rhino first before saving. It's basically a cache of some of Rhino's display information."

Mark

Hi Mark, well some other people have requested it before too, and it would be useful for use with some particular programs like that iPhone app.

So it's not necessarily a bad idea to have it, but I have not yet been able to figure out a good way to do it in the regular file save UI that doesn't seem weird... Something like having 2 different kinds of 3DM files that you could save to from the regular file type list one of which can't be loaded back in and the other is your main save file type is pretty weird.

Maybe at some point I'll be able to add it as some kind of optional plug-in command or something like that so that it won't make for a confusing regular save UI.

- Michael

Would it not help to have it as a saving option at the end of the list after illustrator ai - RhinoMesh(3dm). Before it saves it gives you a warning that the file will not be compatible back into Moi - asks you to confirm. If it is at the end of the list it is less likely it would be used in error.

Hi 3dcnc,

> Would it not help to have it as a saving option at the end
> of the list after illustrator ai - RhinoMesh(3dm).

That would be better than having it right next to it, but I'm still pretty wary about it.


> Before it saves it gives you a warning that the file will not be
> compatible back into Moi - asks you to confirm.

It's pretty difficult to convey this warning information very well - too short of a message can be too cryptic and not explain things enough. Too long of a message tends to make people ignore the whole message.

So I don't quite like to rely on this kind of warning message.


The side effect of saving to the wrong kind of 3DM file and thinking you had all your full data safe could be pretty catastrophic...

- Michael

Maybe it should save both. if you try to save the meshfile. the backup suface file is overwritten evrytime you use the option.


file2.3dm and file2_mesh.3dm

Sometimes you need to learn the hardway to keep things simple ( I speak from experience). I have run out of ideas for this one.


Thanks for the feedback anyway.

Hi Mark,

> Maybe it should save both. if you try to save the meshfile. the
> backup suface file is overwritten evrytime you use the option.
>
>
> file2.3dm and file2_mesh.3dm


So you mean actually modify the file name that the user types into the file save box and stick _mesh at the end?

That kind of file name alteration might be kind of weird for the case where someone was mainly wanting to generate the mesh file...

The way that might be less weird overall could be to have a plug-in that would do this, it could be something like a "ExportMesh3DM" command that you could install and access from a plug-in menu in the future at some point when I've got a menu for such things set up. That would keep it more totally separated from the regular save mechanism.

- Michael

What mesh density would you save out in the 3dm file? NGons?

At the end of the day, this is solely a problem for Apple and their Ipad, not MoI. The Ipad need to be able to read polygon files, like OBJ.

Hi Steve, yeah surely sooner or later someone will make a viewer app for the iPad that can load some common polygon file types like OBJ.

Actually I guess the one that was mentioned in this previous thread here seems like it can do it now:
http://moi3d.com/forum/index.php?webtag=MOI&msg=3827.1

- Michael