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View Full Version : Zbrush Vs Sculptmesh


David McSween
02-09-2006, 05:02 AM
What has Zbrush got that we don't?

D

Blikkie
02-09-2006, 05:54 AM
Exporting normal maps to start with. Really. Sculptmesh may prove te be convenient in some cases, but it can't even stand in the shadows of Zbrush.

ZanQdo
02-09-2006, 07:35 AM
Itīs just not the same, z-brush is a voxel sculpter, sculpt mesh is a poligon tool, but Ideasman, the author of sculpt mesh said he will to try voxels now, lets see what happen :-)

FreakyDude
02-09-2006, 08:32 PM
From a user's view:
well sculpmesh basically just pulls or pushes vertex down, so here's how I make it work for me, I make something lowpoly, make sure there are plenty of cuts to make the overal distance of longer edges as short as the shortest edge. Then subdivide the lot a few times so you have a hell of a lot of vertex and start pulling pushing them.

You can get the same effect non interactively (in max, but blender prolly has something like it, I'm really tired so I'm not gonna look for it)by unwrapping an object, give it a displacement map, and use a certain (grayscale) image that pushes or pulls the verts. If you want more details, just subdivide the lot.

Zbrush can probably create a geometry based on where you paint. I doubt that all it does is push and pull stuff.

phonx
02-09-2006, 09:13 PM
Sculpt mesh is way too slow with complex mesh while Zbrush still fly!!:twisted:

LetterRip
02-09-2006, 11:09 PM
Actually I don't think that zbrush is a voxel sculptor, I think it uses voxels for most other things but not for mesh sculpting.

Zbrush can probably create a geometry based on where you paint. I doubt that all it does is push and pull stuff.

Zbrush when sculpting geometry only pushes and pulls.

You can export normalmaps with Blender there are like four different methods now, none of them are particularly convenient though...

Biggest differences are (for sculpting)

geometric density - ZBrush is usable for a couple of million polygons, sculptmesh less than 100,000 at a time. (well actually cambos is bbrush and mine is sculptmesh - and works somewhat higher density meshes - but still both scale to much less dense meshes - partly due to some issues in python, and partly due to for instance cambos version using a pure brute force).

how mirroring works

multiresoluion mesh

the scaling issues - somewhat can be ameliorated by switching to C, but most of it is just smarter algorithms. sharpconstuct I've given the author a number of optimization hints and he told me he has had some huge speed gains (as far as I know hes not committed them yet).

multiresolution mesh will require gurus either Ton or zr probably.

LetterRip

Womball
02-13-2006, 06:55 AM
I thought they were called pixols? Unless voxels is the generic term for it. I have been reading about the latest blender at blender.org and it seems that they upped the total poly count to about 125 million. I know zbrush is propbably higher, but its quite an improvement. Although they seem to have an issue with memory or something? At 9 million polys it used like 910 mb. Which is kind of high.

Inktvlek
02-13-2006, 07:41 AM
From a PDF at pixologic.com:

"Right now ZBrush is a pixol paint program. Pixols are a proprietary variant of voxels (3D pixels). Voxels don't usually have more than an RGB value and an x,y,z position in space. You can join voxels into textured geometric meshes or smooth surfaces (metaballs, metablobs, metaparticles and hypervoxels are all sort of the same thing). Pixols do much, much, much more. They have up to 64 channels of information and in the hands of Pixologic's programmers they are unbelievably fast. ZBrush paints full-colour, fully-textured, fully-lit 3D stuff in real time. It's real 3D stuff that you can re-texture, re-light and re-render to your heart's content - but it's not 3D geometry."

there's much more interesting stuff explained in that PDF, but it's protected so I can't copy paste from it and I'm not gonna type more :)

http://pixologic.com/news/DG_Pixologic_zBrush.pdf

bdx
02-13-2006, 12:45 PM
ZBrush has been moving away from pixols. That PDF is from 2000, when pixols were ZBrush's selling point, it basically was more like a 2D paint program with some 3D shading tricks back then. Sculpting and projection painting were added later, and they are not based on pixols, but plain old polygons and 2D textures.

LetterRip
02-13-2006, 02:52 PM
Some suspect that they are actually using a surfel variant, which are also a more robust implemention related to voxels.

I have been reading about the latest blender at blender.org and it seems that they upped the total poly count to about 125 million.

That is the maximum rendering amount for polys in a render, nothing to do with the sculpting tools capabilities. ZBrush instantiates objects to pixols for its background stuff (ie things that have been 'dropped to canvas'. When you are directly working on an object I'm pretty sure it is a regular mesh surface simply because they have some mesh specific behavior. ZBrush has a workable resolution of 2 million polygons from what I can tell in the forums but that has been increased in the upcoming zbrush release.

Although they seem to have an issue with memory or something? At 9 million polys it used like 910 mb. Which is kind of high.

9 million 'real polys' or how much is virtual? Also how much undo buffers?

Blender uses 73 MB ram for object mode 400 k quads/800 k tries of real geometry. 209 MB for the same object in editmode. Note that a single object uses much more ram then the same number of faces stored as multiple objects. So 9 million real polys would be around 821 MB in object mode - however I'm fairly sure that your 9 million figure is actually virtual polygons (ie subsurf polys) which take drastically less ram. ZBrush probably is storing an octree etc so all else being equal should take more ram for equivalent poly count.

LetterRip

Womball
02-13-2006, 03:28 PM
Log (Ton):
Upgraded max limit for faces in render. Up to now, quads were zbuffered
as triangles, with a tag bit to denote which triangle was which part of
the quad. That was hardcoded bit 0x800000, which allows a maximum of
about 8 million quads...

I've made this a nice #define, set to be 16 times larger. So, now the
facejunkies can go up to 128 Million faces, were it not that this will eat
up a load of memory!
I only have 1 Gig in this machine. A test with 9M vertices and 7.5M quads
eats up 912 MB of memory already. If this becomes a real issue, I know
tricks how to make the vertices 20 bytes smaller, and faces 4 bytes, which
would in the above case save about 200 MB. Not much... but probably worth
the try? A much better method is of course 'bucketing' the renderdata per
tile. It's a spec of the render recode, but not a quicky to add.

Also: bug fix in curve code. There was a short counter still, crashing on
large curves with resol set to 1024 http://www.blender3d.org/forum/images/smiles/icon_smile.gif

http://www.blender3d.org/forum/viewtopic.php?t=8095&sid=2af6b6a2845587096662dbf6ba686c19

I'm using this build btw. Seems the lights don't quite render nicely. Perhaps this isn't the same thing?

LetterRip
02-13-2006, 04:04 PM
There was a bugfix in lights stuff shortly after that commit.

there is s difference between ram usage of renderer and ram usage of objects. It is unclear whether my estimate is low or high for ram of objects.

LetterRip

David McSween
02-14-2006, 01:53 AM
Does this all mean that I CAN'T do the Zbrush thing in Blender? If there are similar workflows could someone point them out?

Sorry for my ignorance.

D

pnoland
02-14-2006, 02:43 AM
ZBrush has been moving away from pixols. That PDF is from 2000, when pixols were ZBrush's selling point, it basically was more like a 2D paint program with some 3D shading tricks back then. Sculpting and projection painting were added later, and they are not based on pixols, but plain old polygons and 2D textures.

The Pixol is still a big feature of Zbrush, they've never shy'd away from that. People forget that Zbrush is a rendering application also, so when you see a rendered Zbrush file you're looking at Pixols. When a 3d object isn't active anymore it's converted to Pixols which is why Zbrush scenes can consist of millions of polygons with no slowdown.

You can use zbrush with Blender but currently it's not so pleasant. :/ I'm hoping they are planning on incorporating micro displacement or proper normal mapping render features in an upcoming release. I'd love to use Blender more but for character work Zbrush is a big part of my work flow so what ever I render in needs those one of those two features. You can, however, use Zbrush displacement maps on the bump channel in Blender for so-so results and always import your color texture map from zbrush. That's a huge feature of zbrush that people neglect also, it's a top notch texture tool! I enjoy using Zbrush for most of my texture work then BodyPaint. :) ...er, sorry that was kind of off topic. ;) Now that Blender has a node based material editor I'm going to try to work out a Zbrush > Blender workflow and try a tutorial on the subject when I find something that works decently.

LetterRip
02-14-2006, 05:34 AM
Does this all mean that I CAN'T do the Zbrush thing in Blender? If there are similar workflows could someone point them out?

I'm currently working on a C based sculpting tool for Blender no idea what sort of speed I'll end up with nor how soon I'll finish. Currently I'd recommend SharpConstruct, but it is linux only right now, probably will be working on windows in less than a month.

LetterRip

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