export / import with Zbrush

[bobro]

Hi...waiting for a new webinar ... a question:

Why I have an object modeled with TSplines, converted in polisurf nurbs and then in obj format (maximum of meshes) to export a Zbrush for texturing...I see in Zbrush no quality of meshes and I "Divide" ( I'm a beginner in Zbrush) to improve the quality, before texturing, but appear in the obj the estrange caracteristic lines where the surfaces created in TSplines change to Nurbs for star-points? The texturing .obj I open then in Rhino weight 768mB!!! Imposible to offset mesh for the thickness...
bobro

[Matt Sederberg]

I'm not a ZBrush user....

but I think you'll want to convert to obj from the T-Splines box mode. Skip the step in converting to NURBS. That should give you a better model to work with in ZBrush.

[SDS]

Mr. Sederberg is correct; box mode TSplines exported as obj work fine in ZBrush.
Note that ZBrush prefers solids, i.e. a closed mesh. Any open mesh will contract along the model's edges when subdivided but this can be minimized by adding extra "reinforcement" edges.
You can export a Rhino polysurface as an obj and open in ZBrush, where it can be used (painted, moved, etc.) but cannot be subdivided or it explodes along the Nurbs' surface edges as you show above. DynaMesh usually works good with Nurbs based objs and converts the Nurbs based patchwork into a single mesh.
After subdividing a few times in ZBrush a model will quickly become very dense- too dense to work with in Rhino.

[bobro]

Hi guys,
like Matt said me now I see my open form (no solid ) aparently well...If I divide don't appear
this lines...

-SDS...I'm a beginner in Zbrush and I have to finish a work of texturing in jewellry:

1-In this moment in my object I don't understand and see..."Any open mesh will contract along the model's edges when subdivided but this can be minimized by adding extra "reinforcement" edges." but I will study this question...

2-What is DynaMesh? I don't see dynamesh in tool/geometry window of my tryal Zbrush

3- I have now my obj very light (114 kb?!?..convertion from box mode to obj in rhino) in zbrush...I try dividing it at level 5 and I add some textures(look good)..save this like obj (43MB!!!) and open in Rhino where I need ,I think ,only the thickness and some booleans but

...ok for a boolean
but when I try to offset mesh to have a 1.4 mm of thickness Rhino 5 crashes
Thankyou

[bobro]

If I "thicken" in Tsplines the workflow seems better but I lost the control of the thickness paiting and moving,...in Zbrush...

[SDS]

1.) Poor choice of words on my part..... by "reinforcements" I mean extra edge loops. These will minimize the contraction.
2.) Dynamesh was part of Zbrush revision/upgrade v4r2. Pixologic.com can explain it better than I can.
3.) How many polygons in the model? It's very easy to get the model so large that Rhino becomes so slow that it is un-useable, though I've not seen a crash from this. I make my models in Rhino/TSplines then use ZBrush for adding details, color, and rendering. I don't know how to get the textures from ZBrush back into Rhino.

I don't understand what you are trying to say about thickened TSplines.

[bobro]

Thankyou SDS,
I design jewels for produccion and I need a final solid , a form with a constant thickeness and after modeling in Rhino /T-Splines a surface and texturing this surface in ZBrush like an obj object ...I need now a perfect Thickeness.. I don't know if Zbrush can...I will try with Magic of Materialise...
In any case I'll try to have v4r2
bobro

[YloG]

Hi Bobro


First off let me appologise for my rotten english. Now on with the post. Im not entirely sure this will help but it's pretty much the way i work with all this software, im very new to it all , actually im still on the trial versions of t-splines. But this is what the mighty internet has tought me and it works for me. Im a jewler too by the way. So in rhino/ t-splines you want to make your base piece ie. a ring shank or pendant, i would suggest that basics like size and thinkness and stuff should be taken care of now. Then in box mode export as a obj. Another thing obj's don't hold precise messure only it's messures relative to it's self, so that size 10 ring when you export to obj is not a size 10 anymore, but the thickness relates to size,so after your detailing in zbrush you need to get it back to rhino for resizeing and booleons and stonesetting ect. Im having a hard time expresing myself in english but hope you get the gist of it. Then import in zbrush divide and make your detail work, this will send your polycount up. On the pixologic.com you can get the a free plugin called decimation master, and this will make it posibble to cut your active point count way down without making your model look bad. I usually set my pointcount down to bellow 50000 active points, if i don't do this rhino crashes:D, it will destort your surface a bit but for jewelry it doesn't really matter the buff will take it out later Then export as obj, import in rhino, at this stage i leave it as a mesh, it lets me do booleons and scale and the finishing stuff, and i can't seem to convert it to nurbs or t-splines succsesfully, then exp as a stl for printing. Hope it helps.

[Rehan Sheikh]

Hi guys,
like Matt said me now I see my open form (no solid ) aparently well...If I divide don't appear
this lines...

-SDS...I'm a beginner in Zbrush and I have to finish a work of texturing in jewellry:

1-In this moment in my object I don't understand and see..."Any open mesh will contract along the model's edges when subdivided but this can be minimized by adding extra "reinforcement" edges." but I will study this question...

2-What is DynaMesh? I don't see dynamesh in tool/geometry window of my tryal Zbrush

3- I have now my obj very light (114 kb?!?..convertion from box mode to obj in rhino) in zbrush...I try dividing it at level 5 and I add some textures(look good)..save this like obj (43MB!!!) and open in Rhino where I need ,I think ,only the thickness and some booleans but

...ok for a boolean
but when I try to offset mesh to have a 1.4 mm of thickness Rhino 5 crashes
Thankyou

Dear Bobro,
after subdividing the surface you get a smooth but millions polygon model, and you need to reduce these polygon to work back in rhino, well! there is a plugin in zbrush called decimation master that will magicaly reduce the polygon counts keeping the smoothness alive , reduce untill you are satisfied with surface quality, then export back as obj, and you can work back into tsplines on this obj mesh

[bobro]

Thankyou Rehan Sheikh and YloG,
excuse me for my english too ...
I 'm seing our posts in this moment , I will download this plugin...
YloG...The thickness in Rhino before export in Zbrush? I think thath then texturing and moving ,you will lost the controll of this thickness...(?).I work a surface in Zbrush.
Another way that " offset mesh " of Rhino 5 is the program Magic ( converting obj in stl before) for bigs reducing meshes, thickness, booleans,...
bobro