Here a new experiment with Moi3D and nurbs surfaces, this is a part of mi own path on modelling clean surfaces in Blender and imported these in Moi3D. I just discovered a new thing, by an intuition, from the approximation of NURBS and I noticed is possible to make solid from different patches when they are very close together
I've reduced the gap from two subdivided surfaces in Blender and I imported them into Moi3D and I was able to join them together very nicely and make a solid objects from those surfaces imported with different Control Vertexes . I'm going to new frontiers on surface modelling with both application.

below the example from Blender to Moi into solid :)

here two different blender surfaces with different Control vertex with a small gap between.


the imported surface and joined then added more surfaces with Moi and joined into final solid :)


More subD surfaces from Blender with different topology and CV in one solid edited with Boolean inside Moi3D nurbs :). Just discovered the basic rule for a good conversion and create a nice modelling with both application :)

With what function to Join (for create the missing surface) in Moi ?
Or the missing surface is made in Blender ?

Hi in the first post before editing, I've added the missing part with Moi3d, now I've made a new experiment and only the boolean was done in moi3d after joining all different surfaces from Blender into one regular solid with moi3d.

Have you the Top Surface (grey) and bottom surface (green) who arrive in Moi ? (and in what format ? )

<< I've added the missing part with Moi3d
with Blend function ?

<< after joining all different surfaces from Blender
With what functions ?

Yes this are the surfaces created in Blender, and they are imported as subD from an Obj file without applying the modifiers and in the recent Blender releases there is also an option to better predict the result and is under subdivision modifiers that preserve the corner like what happen into moi, is called "Keep Corners" under advanced options of modifier labeled "Boundary Smooth"
Below I've attached the whole file of this experiment.

THX for the Infos!

But i am perplex :)
here that i obtain by _import OBJ your file by Max Smirnov

What is your method now for fill the "gap" ? Some are overlaping...
You kill faces...& redraw a vertical rectangle... or Polyline+ plane or...

Just redraw or extract "Profils" for make surfaces ? There is a missing link in the general process! :)
I surelly miss something!

import the obj directly with Moi3D V4 using the SubD option, not as an other mesh object or maybe convert them into subdivision surfaces after import with the old script maybe works even with it.
The gap was reduced manually with zooming the into it and byy moving the control vertexes near to the edge, this is my workflow with Blender.

So yes very cool with the SubD Import From File!
Just to Union and we have a perfect solid! :)
But i suppose it's an hard work in Blender for Joint all points first...
and a little work inside Moi for clean lateral faces! :)

Yes a bit complex with Blender but I'm on the way, Ive looked many advanced modelling tutorials with Alias and I got this intuition but I think I can make a good interoperability between Blender and Moi3d I'm trying to reach the best surface export and import, this also gave me more skill on both subdivision and Nurbs

Single surf more complex surfaces and more problem come out, I need a snap with capability that interact with subdivide surf. but I think with a practice I can make solid from multi split subD patches with different topology and CV a good sewed surfaces below an old test with reduced gap but this has some issues on edges and isn't yet well done. but I'm happy with this new strategy :)

Blender multi subD patches


moi multi Nurbs patches


and sewed surfaces into one but has some issues on edges not perfect


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I've aligned two surfaces better in Blender and I edited with a bevel on edges with G2 continuity, now I'm happy, I have to practice

Blender aligned different patch


points shown in Moi3d


And beveled edge with G2

My Y fillet attempt with #Blender Nurbs surf multi patch, imported in #Moi3D via Obj format and converted in Nurbs with SubD command
This is a try with Blender for G2 continuity.

Blender Nurbs Bézier patches


Moi3D sewed surfaces imported via SubD command from and OBJ


Control Points


Control Vertext of multi multi patches bèzier nurbs surfaces

And for now this is the latest more complex and also a bit messy surfaces and very high density, not the best way.

I found the right workflow to use edge crease with Blender, you need to set sharp edges at the crease edge and also use the edge split modifiers after the subdivision modifier the subdivision modifier must be at an adequate level 1 for high mesh resolution up to a medium level (2) for a good result of the surfaces in Moi3D.

This model below was imported without interventions or anything else between the two applications, I only exported the file from Blender by applying the modifiers.

I hope it will help those like me who are looking for a solution of continuity between the two applications.

Now with Blender you can also set the angles in the subdivision options by checking the keep corner option, and this helps a lot in the modeling phase to check the subdivision surfaces.

Seems very cool! Nothing to redraw inside MOI ?

No I've imported the 3d model only, but that depend also on how the model topology was made, I made many test over the past months, but the split edges also manually can make the same result, when you import the OBJ file as SubD with Moi3D.

Hi pafurijaz,

Any chance you'll make a tutorial?

Respectfully,
MindSet

Hello, and thanks for your interest, I hope to find the time to create some guidelines on this topic that I have been analyzing for years now, however, the summary of the procedure with Blender is very simple, but this implies that you also know the use of Blender.

In this case as mentioned above and in other discussions I have started regarding this topic it is that Moi3D has a subdivision conversion that does not support hard edges, but you can work around the problem in various ways, one of them is that you can divide the surfaces of subdivision in correspondence with the sharp edges you want to obtain in Moi3D, I have adapted my method to this and I can predict how I should do this.

Assuming basically that you have a model with sharp edges all you have to do is select these edges in edit mode and assign them a sharpening attribute. "edge mark sharp", and add a edge split modifier that will use this information of sharp edges and split them into export phase. when you apply the modifier with OBJ exporter add-on for Blender.

I recommend to do various experiments and you can better understand how Moi3D works in creating surfaces starting from meshes for the subdivision surfaces, however as soon as I can I try to give a brief guide but I hope that others can now help you and give you some indications on how to do it.

Greetings

https://blenderartists.org/t/blender-add-on-export-to-iges/1324178

The author added a plug-in in Blender