3D Asset Workflow: Sculpting

Summary

• Sculpting means creating a highpoly mesh in e.g. ZBrush, which can then be used as a reference model for the lowpoly mesh
  • The highpoly mesh is never used in the game as is, but its information will be baked onto the game-friendly lowpoly mesh
• Troubleshooting

Sculpting Workflow Steps

1. Prepare a base mesh in Modo OR start with a primitive shape in ZBrush
   • You can also recycle models you have done before to speed up the process
2. Make sure you have everything in the correct scale from the very beginning - it helps to have a character model from the game you are working on as a subtool in your scene
   • For reference, the characters in the Trineverse games are 2m tall
3. Keep the resolution of the mesh as low as possible at first, until the general shape is established
   • Show this version to the AD before adding more subdivisions and details, as it's easier to make possibly required changes at this point rather than later
4. Keep the big picture in mind at all times!
   • If your model (or set of models) consists of several pieces, make all of them as a rough low res version first, NOT one piece at a time from start to finish
5. Keep checking the asset from the distance in which it's probably seen in the game, to make sure the detail level is not too dense and the silhouette is readable
   • If some of the detail work is smaller than one pixel on the screen, it's be unreadable and might flicker
6. Once the asset is otherwise finished, it is usually a good idea to add a layer of damage and scratches etc
   • Leep in mind the possible mirroring and tiling of the UVs
     • Big dents and other details will repeat if you are not careful!
7. Trine style assets should be crooked and not exactly symmetrical, but keep the sculpt version symmetrical if possible, so that the retopo is easy to do
   • It'll be much easier to have a clean symmetrical sculpt to retopo and bake, and modify the final textured lowpoly mesh to be bent, crooked and unsymmetrical
8. Once you are happy with the sculpt, use Decimation Master to make the mesh lower resolution while keeping the details
   • You can decimate to the point just before it starts to show too much (keep the game camera distance in mind here too)
     • You can use this decimated mesh for both retopo in Modo and baking in the Substance Painter
9. Name all your subtools
   • They should have a suffix, e.g. _hp or _high, to separate them from their lowpoly counterparts when baking
10. FBX Export the subtools to one FBX, which contains all your highpoly meshes
    • If the model's scale is off, check troubleshooting
11. Import to Modo for retopoing

Sculpting Tips & Tricks

• ZBrush can feel a bit intimidating for a beginner, but there are tons and tons of free learning material online

Good sites for more ZBrush info

• • ZClassroom
  • YouTube
    • For example:
    • Intro to ZBrush
    • Michael Pavlovich zbrush tricks and hardsurface stuff

• Everybody has their own way of working in ZBrush
  • You can use any techniques you want and it's fine, as long as the resulting model looks good!

How to Start Sculpting in ZBrush

• This guide image is meant for people who aren't familiar with the program, so this can make the very first steps much easier
• Here you can also see one way of customizing your ZBrush layout and the brushes this artist uses most often
  • Customizing your layout is really important for quick and smooth working, so don't be afraid to do it!

How to customize your ZBrush's layout for better workflow

• Editing the positions of the different interface buttons etc can be done in the customization mode: Preferences -> Config -> Enable Customize
  • Now with holding CTRL+ALT, you can drag and drop different features from the menus to your custom setup on the sides of the viewport, and rearrange their positions too
• When you are done, remember to turn the Enable Customize mode off and Config -> Store Config and Save UI

Using a Base Mesh

Guides for using a base mesh

• You can use a base mesh you make in Modo before starting the sculpting
  • You can also skip this part and start in ZBrush from a basic primitive shape of your choosing
• Base meshes can be useful especially in hard surface modeling
• You can also use some of your old sculpts or models as starting points
  • If you often make similar models, like humanoid characters, you might want to start a library of base meshes to make your workflow faster

Exporting the base mesh from Modo

• Separate mesh layers exported from Modo convert automatically to subtools when using FBX, and the scale stays consistent when you use the same format
• Once you have modeled the base mesh, export as FBX from Modo
• In Modo, go to Game Tools tab and use the following settings:
  • Export file: FBX 2014
  • Export type: Export selected
  • Check only: Save Geometry (other settings don't matter at this point)
  • Units: Millimeters (might depend on what is set as default units in Modo)
  • Scale multiplier: 1.0
• Select the mesh layers you want to export and Export As
• These settings make sure that the mesh scale stays the same in both Modo and ZBrush

Importing the base mesh to Zbrush

1. Go to ZPlugin > FBX ExportImport > Import
2. Drag the model to the canvas
3. Select Edit Mode from the top left menu

Sculpting Techniques

Zbrush Tutorial: Panel Loops Ornament Technique

• Great technique for creating surface models and ornaments
  • Features are used in this video:
    • Panel Loops
    • Masking
    • Symmetry
    • Morph target (kind of a layer that can be "erased")

Sculpting Tip Gallery

• 

  General direction should be simple and all the forms should support that same flow for a clear and readable, flowing design

• 

  Shape language: straight v. crooked

• 

  PHOTO:Multiple Sources</small>

• 

  90 degree angled bolt can look very flat when viewed from top directly, while beveled version looks good and three dimensional from all the angles

• 

  Details should have depth and not just look like they are drawn on

• 

  An example image of adding variation to a tree trunk

• 

  Tree flow example

• 

  Tree flow example

Sculpting a Set

• Try to always think about the most optimal way of creating the set
  • Don't create unnecessary unique pieces - recycle whenever you can!
  • You can also save texture space by having tile texture or trimsheets for the whole set, or just some parts
  • You can make a set of only few pieces, and use that to build various assets
    • For example, if you make a chair, you can just make one chair leg
      • After retopoing and UV mapping it, copy & paste the chair leg so that you have four legged chair
• Optimizing & recycling is the key!

How Many Variations?

• Often with environmental 3D assets, the task is to sculpt a set of assets that can be used in many ways by the level artists
  • It can be e.g. a set of trees or a set of modular pieces like fences, that can be combined together in several ways to create different arrangements out of the same pieces
• With organic stuff like trees, plants, rocks etc., a good amount is usually three (3) different variations of the same thing
  • Having too many variations is bad, because more time is used to make them, but not much more value is added to the set
  • Don't make extra variations just in case they are needed, make the optimal amount and once it's used in the game, we'll know if more variations are needed - only make them if there is a real need
  • The amount of the asset variations should be optimized as well as the geometry of the model
  • Level artists can work wonders even with one good rock asset by rotating and scaling it
• To create an optimal set, discuss with the level artists and ask what their preferences are
  • It's important to keep general assets quite general looking, as they are used a lot around the levels
  • If you make three variations of a tree/rock/etc. make sure that they are different shape/size with each other to get the maximal variation out of them
  • Make the different sides of one asset look different, that way you have lots of variation even inside the one asset
    • It can be copied and rotated to make look like a different asset

• One asset viewed from four directions = looks like there are four different assets:

• These three variations of the same type of tree are enough to build a forest
  • Notice how they all have different shape but are still quite general:

Exporting from Zbrush

• When your sculpt is finished and decimated, it needs to be exported from ZBrush
  • After that, a lowpoly mesh can be created in Modo via retopoing on top of the highpoly mesh

Decimate

• Once you are happy with the sculpt:

1. Use Decimation Master to make the mesh lower resolution while keeping the details
   • Decimate your sculpt using Decimation Master in the ZPlugins tab
2. You'll first need to pre-process each piece, and then decimate
3. You can decimate to the point just before it starts to show too much (keep the game camera distance in mind here too)

Color ID

• Apply solid colors to your sculpt using polypaint (Color > FillObject)
• This will later be used as an ID Map in Substance Painter, so use the same color when coloring parts that have the same material
• If you plan to have only one subtool/retopo mesh, you can also use polygroups instead of polypaint as IDs for faster results, but the same polypaint can be applied across subtools whereas polygroups cannot

1. Clean up your subtools
   • Figure out which parts of your sculpt will be separated when baking, and group them up under the same subtools
2. Name the subtools consistently
   • Each subtool should have a suffix such as e.g. _hp or _high - it doesn't matter as long as it's the same for all of them
     • This is to separate the highpoly models from their lowpoly counterparts when paking

• An example of subtool naming:

• A highpoly sculpt with different materials masked using polypaint/vertex color:

Exporting

• You can use either FBX or OBJ for exporting meshes out of ZBrush
  • FBX is usually the best option as it keeps the separate subtools as separate layers in Modo
  • OBJ can be used if you only have one merged piece, and you don't need to bake any parts separately

Exporting as FBX

Exporting as FBX

• Export your sculpt using ZPlugin > FBX ExportImport
• FBX should be used since it retains the polypaint/vertex colors and named subtools in one file
• Use the following settings:
  • Visible
  • FBX 2014
  • bin
  • MayaYUp
• Then the FBX can be imported to Modo for retopo
  • In Modo's FBX import dialogue, leave load mesh smoothness unchecked
    • Zbrush adds two subdivisions to the FBX export - unchecking smoothness removes this
  • There might be some scale issues when exporting as FBX, check the troubleshooting page if this happens

Exporting as OBJ

Exporting as OBJ

• One subtool can be exported as an OBJ
• It's done from the Tools menu "Import", and by selecting the file format OBJ
• OBJ format doesn't have layers like the FBX format
• OBJ scales should work nicely as is when exporting from ZBrush and importing to Modo
• Then the OBJ can be imported to Modo for retopo ("Import as static mesh" option recommended)

About export scales

• Troubleshooting
• ZBrush uses Mystery Units™ and doesn't recognize the metric system
  • What ZBrush calls "scale" is actually the size of the ZTool's bounding box in Mystery Units™
• In general, we use millimeters for everything, but other units should work as well - as long as they are always the same across all applications
  • 1 unit -> scaled to 1000 units = 1000mm = 1m
  • To fix this, once you are ready to export, go to Tool -> Export -> Scale

Updating ZBrush

• There are two kinds of updates for ZBrush:
  • Smaller updates that can be done with the ZUpgrader.exe found in the Program files (For example: C:\Program Files\Pixologic\ZBrush 2022)
  • Bigger updates where the version number changes (For example from version 2021 to version 2022) and for these the ZBrush needs to be completely re-installed
• When updating ZBrush to a completely new version, you need to make some effort to get the settings from the old version to the new version

The UI and Hotkeys settings

• In the old/current version of ZBrush, make sure all your settings are up to date and saved
  • Preferences -> Config -> Save UI
  • Preferences -> Hotkeys -> Save

• In the new version of ZBrush you can then load the UI and Hotkeys settings you saved from the old version
  • Preferences -> Config -> Load Ui -> Load the file you just saved in the previous version -> Store Config (to save as the default in startup)
  • Preferences -> Hotkeys -> Load -> Load the file you just saved in the previous version -> Store (to save as the default in startup)

Plugins, Custom Brushes, Custom Materials, Custom Alphas

• Still missing from the latest version are the
  • Plugins
  • Custom Brushes
  • Custom Materials
  • Custom Alphas

1. Go to the previous version's startup folder (for example C:\Program Files\Pixologic\ZBrush 2021\ZStartup)
2. Copy the custom plugins from the startup folder (for example C:\Program Files\Pixologic\ZBrush 2021\ZStartup\ZPlugs64) and paste them to the new version's equivalent folder (for example C:\Program Files\Pixologic\ZBrush 2021\ZStartup\ZPlugs64)
3. Do the same for the Alphas, BrushPresets and Materials and any other possible customized things that you might have in the old version
   • For the ZbBush default things it's best to keep the new things and not replace them with the older versions in case there might be some changes in the new version
   • For example don't replace the ZStartup -> ZPlugs64 new version folder (For example TransposeMasterData_2022) with the older version (For example TransposeMasterData_2021), those have the version year number in the end for a reason.
4. If you start getting some weird pop ups about missing files when opening the new version of ZBrush, it might be that you have some old version folders accidentally copied to the new ZbBush folders

Other settings

• Document:
  • Adjust up the Width and Height -> Resize to cover the full viewport area
  • Bg color: Range 0
  • Save as Startup Doc (The settings will be saved as default)
• Material -> Save As Startup Material
  • Select a material you want to always be the default when opening ZBrush

Frozenbyte sculpt examples

Highpoly model gallery

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Sources

[PHOTO: Trine Flourish Curve Style Guide.jpg] - Source list :

• Img. 1. [Barcelona Steel Door] https://www.pinterest.de/pin/293367363199673143/ (accessed June 5, 2018)
  
• Img. 2. [STD Privacy Gates - ALLIED GATE companyALLIED GATE company] http://www.alliedgate.com/irongates/iron-gate-photos/std-privacy-gates/ (accessed June 6, 2018)
• Img. 3. [Андрій Метельський - Різьба по дереву - різних майстрів. | OK] https://ok.ru/andry.metelsky/album/582642885456/582712663376 (accessed June 6, 2018)