From Moi to Nvil and back how to stay accurate

Hello
I have a project going on in Moi3d.
I want to bring some object into Nvil to make a "shell" around the object and send back to Moi3d.
What is the best format to do this and to import it and back and stay accurate?

Thank you!

Set MoI preferences to metres
Export from Moi in obj format.
Set NVil to metres in preferences.
Import obj into NVil using merge scene.

NOTE: Moi is a nurbs modeler (nurb surfaces). Nvil is a mesh modeler (Polygons).

MoI does not support import of mesh data that NVil generates however you can use the SubD function of MoI v4  to import obj format but it will apply a subdvision to the mesh geometry converting it from polygons to nurbs surfaces.

Thank you!

Ok I did a test created an object in Nvil send to Moi...no problem....with create subD and import Obj both work good.

from Moi export as obj ...merge scene > select the obj file

I see the items in the scene hierarchy ...but nothing is visible

I need these to work to finalize 2 projects.

Tnx!
 

Is the object empty? You can see the amount of polygons it has in the HUD display on top-left of the viewport.
If it is not empty. Select the object in hierarchy window, then View > Viewport Framing > Best Fit and the object should appear.

Ok I am getting somewhere.
In Moi I am drawing in cm. In Nvil I set it in cm.
When I do the viewport fit I can see it ...but I am confused if it is way too big or way to small as I cannot see the grid.

so I send it back to Moi and it is 10 times smaller.
so I either have an export or import problem.

Attached is the object at size in obj.

Tnx!

Attached obj

There are obj import/export scale options, Edit > Options > File Format Options > ...

Ok so I made a cube 10x10x10cm In Moi export as obj re import in Moi and the dimensions are right.
I imported it in Nvil in the file import options I set the import to scale at 0.1 import /export is set at 1.0 the cube and export open with Moi
and the cube is now 11x11x11cm.

So it is close but is this the way to do it?
I have seen the video of the design rage robot where he imports back and forward and seems to go 1on1 scale.

Am I missing something?

Tnx!

I don't have Moi, so can't answer that.
Are there scaling options in Moi's import/export?

Ok I think I got it.
In Nvil import scaling is set at 0.01 but no matter what I did on the export side it will not come correct in Moi3d.

But I found a setting in obj import and changed to 0.909 instead of 1 and now it seems correct.
but there is something weird I made a cylinder 50cm diameter send to Nvil...it seems in Nvil it is 46cm
save open in Moi it is 14cm :/
Now it would not matter whatever the size I have in Nvil...but what matter is from Moi to Nvil and back it should be the correct size. anyone knows if https://www.youtube.com/watch?v=vMFqGodNlno
Luka Mivsek is a member of this forum...he might be able to help out..since he is going Nvil, Moi and back
I use these to make stuff on cnc machines so I need the dimensions to be right.

I am using open scene and save scene as.
Is this the correct way to deal with obj files?

Tnx!

I just did another test.

I set MoI to meters
I created a 0.1m x 0.1m x 0.1m cube in MoI.
Exported the cube from MoI to obj

I set NVil to meters in preferences
Merge Scene > obj
I set import scale to 1
I used the measure tool > measure between snap points
It comes into NVil perfectly to size at 0.1m

If you set NVil preferences to cm and import scale to 1 it comes in perfectly to size also.

I tested your wheels 1302.obj file
When NVil is set to meters and they are imported at 1 scale
Each wheel is 43.7721m diameter x 26.9996m high

Can you test this 50cm cyl. Moi Nvil and back to Moi?

Tnx!

You cannot import mesh data from NVil into MoI v4 (except when using the subd tool in MoI)

If use MoI > subd > create tool to import the obj data it will convert it to a subd nurbs surface which will change its size slightly as the subd algorithm tries to round off all the edges of the cylinder.

I use the import obj script then subd in Moi. so I can boolean fast and accurate.