Updating Sculpts to Mesh for SL

[arabellajones]

A sculpt is a particular prim distorted by the information in a texture. It has all sorts of limits, but there are still a lot of sculpt-based items on the marketplace. The info on the Wiki about tools is horribly out of date, but I thought I'd point to some still-available stuff.

1: I shall stick to Wings3D. This is entirely free and, if you have a legitimate copy of the sculpt map, the texture, you can recover the mesh and put it in a format any program can read.

2: Sculpts have a reputation for being more efficient than mesh. This is a false impression from that days when the comparisons we had were crude and inaccurate.

First, the tool I used. There is a plug-in for Wings3D which can be found here, with a pack of base objects for making sculpts (I checked and downloaded them today)

http://www.wings3d.com/forum/showthread.php?tid=12

As the thread points out, you need v1.4.1 of Wings3D, which can be downloaded from the same site. It will not work with the current version. While you can edit the mesh that can be made with an imported sculpt map, I'd hesitate. Export it in a portable file format, I used a Wavefront .obj file, and edit in whatever program you wish which can save Collada .dae files that can be imported into SL

It depends how big the final mesh objects is, but sculpts have a fixed number of facets, whatever the size. This means far more detail that you can ever expect to see on a tooth, and not really enough on an aeroplane. And the LOD stepping is related to the object size, unless it is rigged to an avatar, when it is related to the avatar size. The quick and dirty way is to not to produce a new, more efficient, mesh, so you don't change the UV mapping. But you can cut the triangle count of the lower LOD models a lot for a small object.

Why do all this? I took a prim-and-sculpt foot I had for a furry character and was able to halve the complexity cost without any loss of quality. And I am not sure I needed to closely match the sculpts. And I do see old sculpt-based items still out there.

This pic shows a sculpt jaw. The teeth look dark gray because each is a distinct sculpted prim, and each facet, over 4000 per tooth, is tiny. The model is still available as part of the Luskwood Bigcats range.

Edited January 1, 2020 by arabellajones

[Kyrah Abattoir]

Few things i'd like to add.

• Sculpts should really be simplified when converted to mesh, since you're not restricted by the same rules anymore, having the kind of polygon density we can see on the teeth, front of the jaw and tongue isn't necessary on the mesh version.
• Making custom lod meshs will most likely be necessary if you want to stay close to the original look of the abject as the camera moves away, automatic lod generation will probably not look as "graceful" as the original sculpt degradation, but that might vary depending of the sculpt.

At this point I would just re-model, unwrap & lod the entire thing using the original as a guideline really.

[arabellajones]

There's some ways in Blender to reduce the triangle count, automatic tools that do an OK job. This view, same item, shows one of the awkward features of a sculpt, the way the wireframe of a sphere is still there. While the complexity calculation has been tweaked to take out the higher cost assigned the long, thin, triangles, they're not good. On this model, the texture on the underside of the jaw is very plain, but you couldn't really do anything else with the UV mapping of a sculpt. I think you could match the original at the "lips" so you might be able to use an existing texture.

I'd be inclined to take the teeth and link them into one single mesh component. Not really a jawbone, but a similar hidden shape with the teeth sprouting from it. With some sort of "even" UV mapping, it could all be one face/material, a glossy off-white. (I reckon too many people use pure white and black, and so lose highlights or shadows.)

[Kyrah Abattoir]

Yes, and while it create funky geometry sometimes, Blender's decimate modifier is much preferable to the uploader's built-in function. (Doesn't mean people should shy away from doing the reduction themselves, if anything, it's good exercise/practicej, SL creators don't do nearly enough direct polygon work)

[OptimoMaximo]

On 1/2/2020 at 1:21 PM, arabellajones said:

This view, same item, shows one of the awkward features of a sculpt, the way the wireframe of a sphere is still there. While the complexity calculation has been tweaked to take out the higher cost assigned the long, thin, triangles, they're not good. On this model, the texture on the underside of the jaw is very plain, but you couldn't really do anything else with the UV mapping of a sculpt.

Just the inherent nature of sculpt prims, really. Although the poles will definitely be a problem to texture regardless of methods and tools used, the odd proportion due to the polygon stretching could be overcome by using a 3d painting software, at the time I was using Mudbox for such works and the projection tools did a great job at placing texture detail, counter distorting the texture itself so to make it appear undistorted on the surface. 

Anyway, I don't know what wings3d is capable of doing now, but I'd say that if remodeling isn't an option, at least remapping the UVs to something better would help greatly, considering that texture transfer could be achieved by most 3d apps from object to object as well as from one uvmap to another within the same object. 

[ChinRey]

1 hour ago, OptimoMaximo said:

Just the inherent nature of sculpt prims, really. Although the poles will definitely be a problem to texture regardless of methods and tools used, the odd proportion due to the polygon stretching could be overcome by using a 3d painting software, at the time I was using Mudbox for such works and the projection tools did a great job at placing texture detail, counter distorting the texture itself so to make it appear undistorted on the surface.

Or you can just redo the UV map any way you usually do it. But if the sculpt's UV map isn't usable, a full retopo may be easier than a cleanup job.

 

1 hour ago, OptimoMaximo said:

Anyway, I don't know what wings3d is capable of doing now

Wings3D's sculptmap plugin has three limitations but only one of them is relevant if all you want to do is convert a sculpt map to dae:

1. It only supports sculpts with 32x32 vertices. (Sculpt maps can come in different shapes and sizes. The limitations are that the number of vertices along each axis has to be 4, 8, 16, 32, 64, 128 or 256 and the total number of vertices has to be 1024 or less.)
2. It only works for meshes with vertices sorted in a specific order. This is of course only relevant for exporting maps, not for importing them.
3. It generates oversampled 128x128 pixel sculpt maps. Whoever made that plugin made a serious mistake here but again, it's only relevant for export and not for import.

I've never bothered using Wings3D as a sculpt-to-mesh converter since Firestorm can do everything it can do and more.

Edit:

Pro tip for sculpt-to-mesh cleanups: Start by converting everything to quads, then join the vertices along the seam (you may want to mark the seam first for reference). This may seem a bit cumbersome but once you've done it, you can work with edge loops rather than individual vertices so it's usually worth it.

Edited January 5, 2020 by ChinRey

[OptimoMaximo]

2 hours ago, ChinRey said:

Or you can just redo the UV map any way you usually do it. But if the sculpt's UV map isn't usable, a full retopo may be easier than a cleanup job.

Well, as much as I agree with you on this, it's not the point of my comment. That was stated in previous ones. The OP stated the obvious problems a stretched topology/UV mapping ratio on the texture implies and why people tended to just color them without actual texturing work. It's my understanding that the OP wants to just convert the existing model to mesh and keep the UVs as they are, which doesn't help against texture stretching.

[arabellajones]

On 1/5/2020 at 6:33 PM, OptimoMaximo said:

It's my understanding that the OP wants to just convert the existing model to mesh and keep the UVs as they are, which doesn't help against texture stretching.

I'm thinking there's a lot of OK-looking sculpt products out there. I listed tools that I know work, with current download links, rather than leaving anyone dependent on that now almost useless official web page. If the creators want to do a quick and dirty conversion, they can.

Chin Rey suggested Firestorm can do sculpt-to-mesh. Is that Build > Object > Save As > Collada or somewhere else? If it is there, fine, but at least we're talking about this, something a bit more useful than vague hand-waves.

 

[OptimoMaximo]

1 hour ago, arabellajones said:

I'm thinking there's a lot of OK-looking sculpt products out there. I listed tools that I know work, with current download links, rather than leaving anyone dependent on that now almost useless official web page. If the creators want to do a quick and dirty conversion, they can.

OH yes that's definitely possible, I'm not saying it's always going to have bad texture stretch. My comment on ChinRey's was that she was saying a retopo would be in order if the mapping was bad, and I was confirming that straight conversion doesn't help. 

1 hour ago, arabellajones said:

Chin Rey suggested Firestorm can do sculpt-to-mesh. Is that Build > Object > Save As > Collada or somewhere else? If it is there, fine, but at least we're talking about this, something a bit more useful than vague hand-waves.

Yes it can do that and it's the feature you're pointing out. Just little warning: last time I used, it exported the visible sculpt LoD as mesh, so to get the mesh at full, make sure to be very close to it when exporting. Of course this behavior can be useful to export a full range of LoDs to go with the converted sculpt 

[ChinRey]

2 hours ago, arabellajones said:

Chin Rey suggested Firestorm can do sculpt-to-mesh. Is that Build > Object > Save As > Collada or somewhere else?

Yes, it is the Collada export function.

 

2 hours ago, arabellajones said:

I'm thinking there's a lot of OK-looking sculpt products out there.

Be careful with that! If you're doing a straight conversion of somebody else's sculpt maps and they aren't released under a CC0 license, you are violating their IP rights even if there's hardly any chance you'll ever get caught.

If you're modifying the model before you upload it, you're in a legal (and moral) grayzone. I've done that myself once but not without permission from the sculpt creator. (It turned out it wasn't worth it btw - it would have been easier and faster for me to make something in a similar style from scratch.)

[Kyrah Abattoir]

The issue I typically have with sculpt to mesh conversions is that the download ends up becoming larger, and with lod models typically worse than the original sculpt (How is that possible right?)