Let's compile a description of the problem for the RL, and put it in FeedBackTracker.
Thanks.

My YouTube channel.

I can't speak to blender using Lightwave as my go to Modeler ( going to start learning Blender) but what about a worse case of deleting different parts then exporting the remaining parts out?( know it might be a long cumbersome work around But...) you would have to do as many times as needed to get entire model out. Luckily in Lightwave I can break down a model into layers and export a layer out as an OBJ.

and as to OBJ and sub-props it works two ways by material identification and by layer identification. I have used both to create a hierarchy which works well in exchange. especially when a FBX model comes in with added layers and wouldn't allow sub-props at different levels. 

These ones from Sen are really good too!
http://city.reallusion.com/ContentPreview.aspx?i=JIC5cb61c612282fd190

Hi Rampa,

good to see that you are trying alternative solutions to skip the 3dX problem: pretty smart! :)
Nevertheless, to create chunks, Blender Cell Fracture add -on works pretty well, it's a pity to not be able to use it :angry:

For the scene I had in mind, so far I dropped the idea to use it and think to go for a solution using RL breakable object package, which has chunks formed as cubes (so not that much realistic), but I do not see other solutions right now.
When I have time, I will ask Warlord (how made some breakable props in the past) if he can uncover the secret about how he did ;) :Whistling:

Cheers

  Roberto

My PC:
OS: Windows 10 Pro English 64-bit / CPU: Intel i7-9700 3.6GHz / MB: ASUS ROG Strix Z390  RAM: 32GB DDR4 2.6GHz / HD: 2TB+3TB  /  SSD: 2x512GB Samsung 860 EVO + 1x2TB Samsung
VB: Palit GTX2080 TI GamingPro 11GB / AB: embedded in the MB and VB (audio from the MOTU M4 I/F) / DirectX: 12

I'm playing with using soft-body meshes for my wall chunks. I have not gotten them completely rigid, but mostly.

Where it gets really strange is the weight mapping. I need each object to have a pure white weight map. Although there is only one material, the weightmap sees a list of materials for each object, but they are the same one. But applying it only applies to one object, even with "effect all materials" checked.

I'll keep at it though! ;)

EDIT
It won't work with soft-bodies. They don't want to follow "self-collision".

Same here.

The problem is that the hierarchy exists in the file but it is "lost" when the file is brought into 3DX.
In reality it is "partially" lost,as the object is ow split into N sub-meshes,which were the children in the exported hierarchy.
N sub-meshes, but one single object... the child objects are gone :(
Worst than this, it is could be a mess to assign the materials in 3DX if not cautiously planned upfront (assuming there is a solution for this).
I haven't made so many trials on this, but so far my attempts to have the same material for each sub-prop, with the ambitious target to get this with 1 click, were a total disaster :w00t:

Cheers

  Roberto

My PC:
OS: Windows 10 Pro English 64-bit / CPU: Intel i7-9700 3.6GHz / MB: ASUS ROG Strix Z390  RAM: 32GB DDR4 2.6GHz / HD: 2TB+3TB  /  SSD: 2x512GB Samsung 860 EVO + 1x2TB Samsung
VB: Palit GTX2080 TI GamingPro 11GB / AB: embedded in the MB and VB (audio from the MOTU M4 I/F) / DirectX: 12

The FBX does work better, but has not proved fruitful for me yet.

I wonder if FBX would work better? I don't know if the OBJ format itself supports hierarchies.

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I could not find a way either.:(

It's a limit at the 3DX step, rather than the modeling step.
I like your idea of open API for 3DX. It should also be a feature in 3DX. Currently we can add a bunch of meshes to a sub-prop, but it should have an option when doing so to make each mesh its own sub-prop.

I have found that if the individual meshes are fairly low poly they can be quite "solid" as soft-body physics. That cannot be turned on and off in the timeline, but it can be baked and then put where it's needed on the timeline.

I'll put in a request for soft-body physics to have settings that make it entirely rigid, no bending of the mesh at all.

I did falling leaves that way once.