PDA

View Full Version : LW OBJ to Video CoPilot Element - fractured pieces not treated as islands



JBT27
12-09-2013, 07:26 AM
I've been experimenting with some shots done in Element, and whereas LW exported OBJs generally work fine with it, I've hit a problem with fractured objects - any object that has islands. Element has a setting which allows it to handle islands in the same object individually, for scattering, displacing, rotating, etc.

It works fine with OBJs from Max, Maya, C4D, Blender, apparently, but with those from LW, the object still moves as one. The guys at VC do not have much experience of LW, as they tell me, and after more tests, there's a hint that it is more likely something to do with how LW is exporting the OBJ. I don't know.

I do know I'm stuck on what I wanted to do, and trying to find a workaround. As I have C4D Lite with Adobe AE CC, and there is fracturing in that, and it imports LWOs, that might be one way. But because of preserving UVs and keeping it all in LW, if possible, I'm wondering if anyone has any idea what this might be. I have looked at altering some of the OBJ export options, but nothing has made any difference. A simple array of cubes is also treated as a single object, so clearly it is not recognising islands in LW OBJ files.

Well, with one caveat: if I apply a different texture to each island, then Element will operate on them. But the workflow should be that an object containing islands, with one texture, can be broken apart using the Element system. I have sent a couple of models and AE scenes over, and they are sending it to one of their modellers for review.

Thanks.

Julian.

Axis3d
12-09-2013, 08:50 AM
I'm getting the same behavior also, using the mac version of LW.

jeric_synergy
12-09-2013, 08:59 AM
Try exporting a VERY simple OBJ from LW and something that works, and take a look at the binaries or an OBJ examining utility.

Like, a one-meter cube, or the simplest OBJ that meets your diagnostic needs (something w/islands I guess).

Also, please report this to FogBugz: obviously, we (and LW3DG) want LW to export in the most compatible way possible.

OnlineRender
12-09-2013, 09:02 AM
hmm strange I have never had a problem even with an obj sequence ... sometimes I need to flip the normals however

JBT27
12-09-2013, 12:08 PM
I have an answer, and it works, although it's far from the most convenient thing at the LW end.

I sent some objects over, and the tech guy instantly said that none of them are 'multi objects' - he opened the OBJs in C4D; ones that worked (theirs) have each piece in a separate layer, mine were in one, despite being polygon islands.

So I took one of the simple LW objects again, fractured it and this time checked 'Parts to Layers'. Despite exporting that through OBJ set to 'OBJ One Layer', it breaks apart in Element as it should.

The other way, which I knew, was to allocate each piece a unique surface, but still keep them in the same object layer - for some situations that could get tedious, unless there are scripts that can do that, and indeed if there are scripts than can take an array of objects and put each one in a separate layer. One of my test objects was an 8 x 8 array of cubes in one layer. For that to work as a Multi-Object in Element, each cube needs to have either it's own surface, or be in a separate layer.

I'm not convinced this is a LW bug or feature flaw, nor with Element - but it's a convoluted workflow for some objects out of LW.

Julian.

jeric_synergy
12-09-2013, 12:51 PM
??? When you sent the 2nd object thru, did the tech guy confirm that it was in multiple OBJ layers, despite the Export Function setting?

Or was it actually in one OBJ layer, but something else was tweeked enough to allow it to fracture successfully?

Obviously if "OJB One Layer" is exporting a multi-layered object, that's a bug, even though it seems to work in your favor. What happens if you explicitly TRY to export a multi-layer OBJ? (IOW, is the switch somehow 'reversed'? Or incredibly badly labeled?)

JBT27
12-09-2013, 03:31 PM
I have received no analysis from them - presumably my saying there was a fix was enough. No disrespect, but they clearly don't use LW and it's not perhaps on their radar. Most of their 3D for AE tutorials are done in Max, with a smattering of C4D. So it's down to us to figure the workarounds, and bugs if there are any.

To which, I do not have any means to analyse an OBJ to see if it contains multiple layers, other than to load it back into Modeler, and into C4D Lite in AE CC. I have exported two OBJs again - one set to 'OBJ One Layer' and the other with that option off.

Both OBJs work in Element's multi-object system, but when loaded back into Modeler, or into C4D Lite, both only show one layer. In both cases I set OBJ Parts to be on - if I set it to off, it still works in Element.

So far, the pattern I see is that if you want to work with poly islands in Element out of LW, with a single texture, you have to place each island into its own layer prior to OBJ export.

Quite what these OBJ options are doing internally is difficult to know, but that may be more evident in other 3D apps than it is in Element - out of my depth on that one.

Julian.

jeric_synergy
12-09-2013, 04:41 PM
Well, I'd definitley wave a flag at FogBugz. It's up to LW3DG to make sure their exports play nicely with all the other kids.

I remember there's something called "TAGS" deep inside LW models, but to my knowledge they're not used or accessible to users. Perhaps it's related to these mysterious elements. --Just throwin' it out there.

Ztreem
12-10-2013, 01:13 AM
There is a tool in modeler to distribute parts to layers, It's in the layers tab and called 'connected to layers'. I hope it helps.

JBT27
12-10-2013, 06:39 AM
Thanks Ztreem - yes, that may help. Though it places the first object in the last layer and then sequences the rest properly starting from the second layer. Not sure if that will screw things up in Element, but I'll give it a go.

Julian.

JBT27
12-10-2013, 06:54 AM
On the subject of this workflow, and getting islands into layers, this one seems good, basing layer order on selection order:

https://www.lightwave3d.com/assets/plugins/entry/connected-poly-to-layer/

Julian.