Blender to Unreal Engine tips

Software:
Blender 2.9 | Unreal Engine 4.25

The following is a list of guidelines for preparation and export of 3D content from Blender to Unreal Engine 4 via the FBX file format.

Disclaimer:
This is not a formal specification.
It’s a list of tips I found to work well in my own experience.
* Some of the issues listed here may have already been solved


Blender Scene and model settings:

System units in Blender:
Define the scene units in Blender as:
Metric unit with 0.01 scale (centimeters)
And model your content correctly using centimeter units.
* Modeling in 1 meter units may seem to be imported correctly into UE4 but will cause unsolvable problems like a skeletal mesh physics asset having incorrect auto-generated shapes, a problem that in my experience can’t be fixed manually.

Transform:
Model your model in Blender facing the -Y world axis, +Z obviously being up (obviously for Blender).
* This way the model is aligned to Blender’s views so the front view displays the model’s front etc.
Make sure to apply your model’s transformations before export.

Armatures:
Make sure the Armature object isn’t named “Armature”.
naming or leaving the Blender skeleton named “Armature” will cause the UE4 importer to fail due to “multiple roots”.
* Also remember some weird related bug with animation scale incorrectly imported, but can’t confirm this now..
No need for a dedicated root bone in the hierarchy. the Armature object is the root of the bone hierarchy.
* See export option below

Texture baking:
Set the normal map’s green channel to -Y.
* This is not critical at all because if baked as +Y it can easily be fixed in UE4.

Metadata:
Blender custom properties import as UE4 asset metadata that can be read by editor scripts for automation purposes.
* See export option below


FBX Blender export and UE4 import settings:

I recommend saving an FBX export preset with these settings.

Optional:
I prefer the export settings to include only selected objects.
* It’s more efficient for me to select the specifics objects I want to export into a single FBX file prior to export, than to delete all the temp / reference / draft objects from the scene.
If you want to export Blender custom properties with to the FBX check the “Custom Properties” option

Axes:
Blender’s native model/world orientation is model’s forward facing the -Y axis, left side facing +X and of-course up facing +Z.
UE4’s native model/world orientation is model’s forward facing the +X axis, left side facing -Y and up facing +Z.
There are axis settings in Blender’s FBX export module, that theoretically, should be set like this:

However, in tests I did, The axis settings made no difference when importing to UE4, even when setting intentionally incorrect upside-down axes.
Maybe the FBX exporter writes these settings to metadata that the UE4 importer doesn’t read..
From my experience, what’s important is to orient the model correctly in Blender (see above), apply the transformations,
And in the UE4 import menu, check the “Force Front XAxis” option:

Geometry:
Make sure either “Edge” or “Face” is chosen in the “Smoothing” option to import the mesh’s smooth shading correctly ans avoid a smoothing groups warning on import:

Optional:
Depending on how much control you need over the mesh’s tangent space,
You may want to check the “Tangent Space” export option,
This will make Blender export the full tangent space to the FBX and make UE4 read it from FBX instead of generate it automatically.
* For this option to be supported, the mesh geometry must have only triangle or quad polys.
In the UE4 import settings, choose the “Import Normals and Tangents” option in “Normal Import Method”:

Armature:
Set “Armature FBXNode Type” to “Root”.
Uncheck the “Add Leaf Bones” option to avoid adding unneeded end bones.
Set bones primary axis as X, and secondary axis as -Z.

Animation:
Uncheck “All Actions” to avoid exporting actions that don’t actually belong to the skeleton.
* Un-related animations in the FBX can also corrupt the character rest pose in UE.
The “NLA Strips” option is useful for exporting a library of animations with the skeleton.
* In Blender’s NLA editor, activate the actions you want exported to the FBX.


Related:
3ds max & V-Ray to UE4 Datasmith workflow

Blender – Modeling character clothes using cloth simulation

Software:
Blender 2.8

This character project is the first one in which I’m using physical cloth simulation in Blender to model the character’s clothes at proxy quality (they will be detailed further manually). learning this approach to clothes modeling demanded a lot experiments, trials and errors to get it right, in this short article, I’ll try to provide some insights, tips, and settings that can speed up the process.

Watch the full modeling process here

General notes and tips:

  1. When modeling the basic shape of the cloth try to “cut” a realistic cloth pattern for your desired cloth model. if you’ll search images on the web for “trousers cutting pattern” or “coat cutting pattern” you’ll find many examples.
    * See images below
  2. Create proper UVs for the cloth mesh when its still flat (before the simulation)
  3. In Blender cloth simulation, isolated edges in the mesh (edges without polygons) are treated as sawing springs, and are an important part of the cloth setup.
  4. Use a low poly proxy model for your characters body mesh, it will speed up the cloth simulation.

Early experiments:

In this experiment I used a simple tubular pants-like mesh that I quickly modeled around the character’s legs and pelvis (not a realistic cloth cutting pattern), with the top (weist) vertices defined as a vertex group with shrinking cloth property.
The result looks like training suit pants. it wasn’t at all what I wanted for this character, but I actually like it and probably will use such pants on other characters or on this one as a secondary look.

cloth_study

In this experiment I started trying to model an actual man’s trousers cutting pattern, and as you see, it still needs tweaking.

Blender_Cloth

This experiment is beginning to produce reasonable results, the undershirt initial shape is still cut too low at the back.
* Note that there is an animated belt collision object to bring the undershirt to it’s shape at the weist

Blender_Cloth_B2

Final Settings:

The final undershirt initial model:

Annotation 2019-12-08 120355

The final pants initial model:
* Note that the belt mesh is a vertex group defined a fixed in the cloth simulation, and that it’s split to parts corresponding to the edges of the pants shape that need to be sawed to it. (see the process here)

Annotation 2019-12-08 120618

The full final cloth setup for the character. the setup includes a low poly collision object of the whole character and shoes, undershirt mesh, pans mesh and animated (contracting) belt collision for the undershirt:

Annotation 2019-12-08 120941

The final cloth simulation:

cloth

cf

cb

Cloth Settings:

Cloth simulation settings for the undershirt:

cloth_undershirt

Cloth simulation settings for the pants:

cloth_pants.jpg

Related posts:
Blender 2.8 Character Project

Blender 2.8 character project

Software:
Blender 2.8

feature

I Recently started a personal character modeling project using Blender 2.8.
The project has the following goals:

  1. Get back to development of creative 3D content (character development, animation, rigging etc.).
    * the last 10 years or so I have been generally doing (and teaching) photorealistic rendering for technical visualization projects.
  2. Get used to Blender 2.8
  3. Practice A sculpting > re-topology workflow.
    * When I learned organic modeling 20 ago, there was no such workflow, you would create final topology from the get go.

I will be video capturing the whole project’s progress and sharing it on my vimeo channel.

You’re welcome to read about the project creation steps and watch the actual work process captured here:

  1. Part 1 – Sculpting – Freestyle rough draft
  2. Part 2 – Sculpting – Refining the model
  3. Part 3 – Modeling proxy clothes and props

Blender 2.8 character project – Part 3 – Modeling proxy clothes and props

Software:
Blender 2.8

This is the third part of a personal project I began working on,
Development of a realistic character in Blender 2.8 for games and animation.

<– Go to the project home
<– Go to the first part of the project
<– Go to the second part of the project

The third part of the project was a ~7 hour modeling session in which the focus was mainly on proxy-quality (rough) modeling of clothing and props.
In this stage of the project, I decided that the creative theme for character will be a tough detective. a sort of an Asian ‘Dirty harry’ character, and this concept was the drive behind the styling of the characters clothes and and props.


Result after part 3:

> Total accumulated work time: ~17.5 hours

 

Some tips and settings for modeling the clothes

 

Blender 2.8 character project – Part 2 – Sculpting – Refining the model

Software:
Blender 2.8

This is the second part of a personal project I began working on,
Development of a realistic character in Blender 2.8 for games and animation.

I will be video capturing the whole project’s progress and sharing it on my vimeo channel.

<– Go to the project home
<– Go to the first part of the project

The second part of the project was a ~5 hour sculpting session focused mainly on refining the model, improving its proportions and anatomical detail, and adding internal parts like eyeballs and teeth.
In this part the character design was developed into a more masculine man and less skinny, the general idea still being an elder Asian action figure.

Result after part 2:
> Total accumulated work time: ~10.5 hours

tt_25.06.19.gif

 

Go to part 3 of the project –>

Blender 2.8 character project – Part 1 – Sculpting – Freestyle rough draft

Software:
Blender 2.8

This is the first part of a personal project I began working on,
Development of a realistic character in Blender 2.8 for games and animation.

<– Go to the project home

The first step of the project is a completely free-style / free-form ~5.5 hour sculpting session in which I’m not really trying to do anything accurate but just get used to 3D sculpting in Blender 2.8.
I’m imagining an elder Asian action character, at this point not sure what he’ll end up being. possible themes are:
ninja, samurai, cyber themed ninja or tough detective.

Result after part 1:
> Total accumulated work time: ~5.5 hours

 

Go to part 2 of the project –>

Blender Skeleton (Armature) Mirroring

Software:
Blender 2.8

To mirror a skeleton (Armature) in Blender:

  1. Create bones for one side of the rig and name them with “.L” for Left or “.R” for right.
  2. Select all the bones on that side.
  3. In Armature Edit Mode choose:
    Armature > Symmetrize

Blender will create mirrored copies of all the bones with respect to the Armature origin and flip their names to names ending with the opposite side.

  • When editing properly symmetrized bones,
    The X-Axis Mirror tool option will simultaneously update both sides of the Armature to maintain symmetry.

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Blender – Bake NLA animation

Software:
Blender 2.79

When you wish to bake your NLA animation mix into one Action,
The Bake option in the Animation tab will not work.
The way to do this is to:

  1. Select the object in Object Mode.
  2. Press Space and type ‘bake
  3. Choose Nla: Bake Action
  4. In the Bake dialog, select Pose, deselect Only Selected, and press OK.
  5. After the process, the Armature will have a new action that is the baked animation.

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