lördag 2 december 2017

PBR shader

The DAZ Importer (development version) can now create Cycles materials using the Principled BSDF, also known as the PBR shader. Here the same car has been imported with Cycles with PBR, Cycles without PBR, and Blender Internal.




(Actually, lightning was made differently in BI. The Cycles renders were lit by an environment map, the BI render was lit by two lamps and composited upon the background.)

The PBR shader makes a huge difference for materials like metals and glass. For characters the improvement is not so clear compared to standard Cycles. Here is the default Genesis 3 Female imported in three ways.


And here is a Genesis 8 character. The PBR variant developed some nasty white spots, e.g. on the neck, which is clearly visible even after denoising. In both Cycles renders the shadow on her cheek is also very jagged. Probably it comes from the hair mesh.



To enable the PBR shader, select the Principled Shader option in the Materials And Textures section of the Settings panel. This is still quite unstable and the option may move in the near future, e.g. to the import options.

måndag 27 november 2017

Hair deformation with surface modifier

In the previous post hair was animated with bones. This works well if the hair only has few degrees of freedom, like a pony-tail. However, for long, loose hair it becomes very tedious to animate the hair by hand. It would be much simpler to do a cloth simulation, but we all know that this becomes extremely slow for high-poly meshes.

In version 2.79, Blender has a new Surface Deform modifier, which can be used to speed up hair simulation. I created a low-poly hair guide and made a cloth simulation for it. The simulation is fast because the guide is a low-poly mesh. The animation was then transferred to the high-poly hair mesh using the surface deform modifier. The modifier is a bit picky; it does not work if the guide mesh contains concave faces, and the hair tends to develop spikes unless the guide is very smooth. By splitting the faces to triangles and smoothing the mesh I managed to get rid of the most glaring problems.

Here is a video that shows my take on it.

lördag 25 november 2017

Winders

This blog has been in a dormant state for a while. There are several reasons for this, one of these was that I started to get tired of the DAZ Importer and on CG in general. However, for the last month or so I started to take up Blender again, learning about the many of the awesome new features, e.g. denoising, HDRI images, shadow planes, and the surface deform modifier. It is also time to actually do something with the DAZ Importer and not just implementing it.

The topic of today's post is something I call winders. Long and flexible objects, such as chains, ropes, whips, or ponytails, often have armatures consisting of many small bones, one for each link. Posing each individual link is tedious, and it is often difficult to get a smooth curve.

Enter winders. A winder is a single bone that stretches along the entire chain, and by rotating the winder you can easily pose all links in the chain in a smooth fashion. Under the hood, a winder is implemented by Copy Rotation constraints with offset enabled. This means that once you have posed the winder, the individual links can be posed on top of that. In fact, there are two examples of winders in the MHX rig: the long fingers that pose the three finger links, and the back bone that poses the entire spine.

 To illustrate the feature, here is a model of Lara Croft (I think). The rig has been converted to MHX and we see the hair bones on the Clothes layer. The ponytail and the hair strands at her forehead are suitable examples of chains to which we can add a winder.





 

With the first bone in the ponytail selected, press Add Winder in the Rigging section of the Advanced Setup panel.










A winder bone is created, and the bones in the ponytail chain gets some constraints. The entire ponytail can now be easily posed with the winder bone.







And here is a short video where the ponytail and hair strands have been animated with winders.

torsdag 14 september 2017

Finally, version 1.2 released

There have been some bug fixes since the latest release candidate. Most importantly, the DAZ Importer has been much better at handling older DAZ files that do not follow the conventions in more modern ones. Stable version 1.2 of the DAZ Importer can be downloaded from:

https://www.dropbox.com/s/jx15t3inlvtd98x/import-daz-v1.2-20170913.zip.

There will be no further bugfixes in version 1.2, because in the next few days I plan to make some major revisions in the code base which may introduce new bugs. In particular, the code that builds Blender objects can be simplified. The complexity was necessary to handle the automatic mesh fitting in version 1.1, but since that feature has now been removed (it never really worked), the code can be made simpler.

torsdag 17 augusti 2017

New release candidate

A new release candidate for version 1.2 of the DAZ importer can be downloaded from https://www.dropbox.com/s/x1tkb0khjycq251/import-daz-v1.2-20170818.zip. There are two improvements compared to the previous RC:
  1. I learned that you can import Poser files into DAZ studio and save them as DAZ files, which can then be imported into Blender. However, these files are slightly different from the native DAZ files, and they caused some errors in the import scripts. These bugs should now be ironed out.
  2. The Rigify add-on was changed in Blender 2.79, which caused Rigify conversion of DAZ armatures to stop working. The new RC should work with both old and new Rigify.

Poser import

Here is how to get a Poser file into Blender. Start by importing the file into DAZ Studio.

Select File > Import

and navigate to the Poser file (.cr2, .pz2, ...). Repeat this step to add clothes, hair, etc.


Apparently the clothes fitting is not perfect.

We could save the character as a DAZ file now, but then we would not be able to pose her in Blender, because Poser figures are skinned with envelopes whereas the DAZ importer only handles vertex groups. Fortunately, we can convert to vertex groups in DAZ Studio.

Select Figure > Rigging > Convert Figure to Weight Mapping.

We get to choose between TriAx and General Weight Mapping. This choice is not terribly important, because TriAx will be converted to general weights in Blender anyway, but General is probably the best choice. here.

This step has to be repeated for every figure in the scene, i.e. for each piece of clothing.

Finally we export the final world-space coordinates to a .json file using the basic data exporter that comes with the DAZ importer. See the blog post on JSON fitting for details.

Now we can import the Poser character just as any other DAZ file. In my example there were a lot of extra nodes that correspond to empties in Blender, but it is easy to get rid of those. Just select the empties by type and delete them.


Rigify

The Rigify add-on was changed in Blender 2.79. I am sure that this is a great improvement, but the update had the side-effect that Convert To Rigify button in the DAZ importer was broken. Should be fixed now.

The meta-rigs are clearly different.

So are the rigified versions of the same DAZ Rig.

The new Rigify has a face rig, but the DAZ importer ignores that. DAZ characters already have a great way to do facial posing, with carefully crafted facial morphs or a carefully weighted face rig, and there is no simple way to map that to the Rigify face rig. The face bones in the rigified character appear on the otherwise unused bone layer 2.








söndag 6 augusti 2017

DAZ Importer version 1.2

The DAZ importer is a tool for importing native DAZ Studio files (DAZ User File *.duf, DAZ System File *.dsf) into Blender. It also contains some tools to make the assets more animation friendly.

Release candidate 2: https://www.dropbox.com/s/x1tkb0khjycq251/import-daz-v1.2-20170818.zip
Main documentation page: http://diffeomorphic.blogspot.se/p/daz-importer-version-12.html

Since the previous stable version was released half a year ago there has been several improvements and additions.
  • A DAZ Studio plug-in for exporting the final world space coordinates for vertices and bones.
  • Limits on the number of facial expressions overcome, using handlers for bone drivers.
  • Material improvements, in particular for Cycles.
  • Posing improvements.
  • Many small bugfixes and additional features.
The most signicant improvement is the DAZ Studio plug-in. In previous versions Wavefront or Collada files could be used to find the final meshes with all morphs included, but this did not always work correctly. In version 1.1 I also attempted to deduce the final locations directly from the DAZ Studio files. While this in theory must be possible (after all, DAZ Studio does it), I never got it to work right, especially not fitting clothes to arbitrary morphed meshes. After I started to use the DAZ Studio plug-in to export the final world-space coordinates, meshes have always looked the same in Blender as in DAZ Studio.

The script has mainly been tested with DAZ Studio 4.9 and Blender 2.78c on Windows 7.

lördag 5 augusti 2017

Windows 10 and non-ascii characters

The Daz importer has mainly been developed on my home computer, although I have occasionally tested the code at work. Both computers are very similar: both run Windows 7 and my user name on both is Thomas, which is a standard Christian name without any strange characters. However, I also own a laptop running Windows 10, which I have never used very much, but I thought that it would be a good idea to test the code on it.

So I created a new user on the laptop, whose user name Åke Öst contains non-ascii characters, and downloaded Blender, Daz Studio, and the Daz importer. Saving the .duf file in Åke's user directory worked fine, and I could also export a json file to the same folder. However, when I tried to import the .duf file, the error below was encountered.


In Python the current user's home directory is represented by the string ~, which in this case should evaluate to

C:\Users\Åke Öst,

but instead Python thinks that it is

C:\WINDOWS\system32\config\systemprofile.

Since no directory with that name exists, the importer can not find the paths to the Daz directories, and the error is issued to alert the users about this fact.


We can inspect the paths at the top of the Settings panel. Both the first Path to DAZ library and the Path to output errors start with the flawed directory and will not be found. Fortunately, this problem is easy to fix. Simply replace the incorrect beginnings with the right one (the paths really contain the substrings "Åke Öst", even if Blender uses a font that makes it indistinguishable from "Åke Ost". Finally press Save Default Settings to avoid having to do this correction every time Blender starts up.


Behind the scenes another problem has been solved. The settings are stored in a file in the current user's home directory, but as we just saw Python failed to find that. If the home directory is not found, the script instead tries to put the settings file in the same directory that the script is stored in. Since this is usually located somewhere under the home directory, the user should have both write and read permissions. At least it worked for me.

The non-ascii characters turned out to cause one more headache. The import script is stored in a single location, and then I have made symbolic links (hard links or junctions in Windows lingo) from Blender's addons folder. This means that I don't have to update the script when a new Blender version comes out, only the links. However, I make the links by running the mklink /j command at a DOS prompt, and that mangles the non-ascii characters. The string "Åke Öst" becomes "+ke Íst", and no link is created.

There is probably some way to make a terminal window understand non-ascii characters, but instead I downloaded the Link Shell Extension, which is a graphical tool for making links.  Worked like a dream. Just be sure to download the appropriate prerequisite package before the tool itself — both are linked to on the tool’s download page.

While non-ascii characters caused some headache, they are still within the UTF-8 character set. The code has not been tested with systems that use Unicode, and I am completely sure that new problems will show up in such settings.