vertex model format how different from wavefront .obj ?

Mistara

vertex model format how different from wavefront .obj ?

vert points, faces, face groups,

noticed some poser figures like Sydney, don't have the normals info in her .obj.

noticed duf content doesn't give the convert to vertex message when taking it into model room for tweaks,
does that mean is already vertex, or rara knows to convert duf automatically?

what info does vertex format have that traditional .obj doesn't?

modelling in carrara is directly vertex?
as long as it stays in carrara it never has to be converted to obj?

 

are we losing information converting vertex to obj, back to vertex?
i usually run a model through uvmapperclassic, just to check there is no 'out of range'. duuno if thats wise now 

 

https://en.wikipedia.org/wiki/Vertex_model -ouch, sprained my brain

TangoAlpha

Vertex Object is the name Carrara uses for anything that's made out of mesh, ie points (vertices - one vertex many vertices), edges / lines and polygons. There are things you can attach to a mesh, sometimes in part, sometimes as a whole: shading domains, named regions (aka face groups), bones, constraints, morphs, position, scale etc. They are not part of the vertex object themselves but they are associated with it. Carrara also supports objects that are not made of mesh -- splines, metaballs, plants, terrains etc. They too can have extra properties associated with them.

Obj is an interchange file format. Its purpose is to get models -- "OBJects" -- from one program into another. It only works with mesh-based models, so vertex bjects. It's quite an old format by insustry standards, and doesn't support things like morphs or rigging. Also its support for materials is limited to image-based shaders: no procedurals.

If what happens in Carrara stays in Carrara  there's no need for obj. But if you want to take the model into some other app, say Studio, or Blender, or UVMapper Pro, or Substance Painter etc., then you'll need to export it and import it to the other program. Obj is the most common "interchange" format to do that in. There are others, such as FBX, but I don't know enough about them to say what the differences are. For me, I have to use FBX to get models into Surface Painter for texturing, since Painter barfs on OBJs (seems to be a problem unique to my Mac as far as I can tell!)

All models in Studio are mesh, so equivalent to vertex models. Of course the internals of Studio are different to the internals  of Carrara, so there isn't necessarily a one to one correlation. One very obvious difference is that Carrara's Z (Zed ) axis is vertical, whereas Studio's Z (Zee) axis is where the Y axis should be. Another is that Carrara works internally in inches, whereas Studio works in centimetres. I'm sure you can identify other differences. OBJ doesn't know anything about units, which means that you have to know something about where the file came from in order to know whether 1 "thing" represents an inch (Carrara), a centimetre (DS), a metre (Modo, Blender) or 8ft (Poser), and whether you need to swap the Y and Z azes. You'll notice that there is a setting on the import dialog for all these.

Aside: Have you noticed the vertex models in the Carrara native content are all on their side? Guess someone forgot to swap Y/Z coordinates when they set them up . . .

To an extent, Carrara can read .DUF files out of Studio. There are a few things it barfs over (Genesis 3, some scaled & morphed models...) and others it ignores (instances...), but a lot of the time you can open the .duf file and see the models. It will mostly read morphs and rigging for props and up to Genesis 2. You don't need to resort to obj for many duf files, although for unsupported types that may be the only way to get the models in (and you'll lose any rigging & morphs).

Exporting an object (say for UV mapper) and then reimporting it afterwards, are we losing anything? Answer: It depends.

Okay, to qualify that. For something like UV mapper, probably not. Mostly. If you don't change the map, you don't need to reimport, so there's no loss there. If you've made the model yourself, you're probably doing the mapping before any rigging or morphing etc, so no loss. The mesh itself will reimport intact (remember to check the scaling & Y/Z swap), but you'll lose those extras. If your model was already rigged or had morphs before you exported it, you'll lose that rigging and the morphs, and have to redo the, You'll also need to reapply shaders.

Hope that's enough info to make some sense!

Mistara

ty

i'se curious what it's 'converting' exactly.  

like, the poser figure obj doesnt have normals info in it, but when exporting (to create a morph), poser adds normals info to the obj file.

3DAGE

It's converting the Vertex information about the model,. from one format, into it's own (vertex model) also rigging and weightmapping UV's etc...

this is why G3 crashes carrara,.

Although Carrara can read the 3d model,. the rigging and weightmapping, are unable to be converted, because Carrara doesn't have that type of weightmapping.  yet.

 

All models will have normal inromation,. (normal is what side of a polygon is facing outward)

Poser has issues displaying reversed normals or back-facing polygons,. it only "shows" the normal facing side.

Open the OBJ for the model from the runtime geometry folder.

All poser / daz models were originally shipped in OBJ,. now DUF and OBZ (different proprietary formats of 3d model)

Hope it helps :)

mjc1016

3DAGE said:

 

All poser / daz models were originally shipped in OBJ,. now DUF and OBZ (different proprietary formats of 3d model)

Hope it helps :)

Obz is just a zipped obj.