UE4 – Python – Importing assets

Posted on by Oded Maoz Erell

Software:
Unreal Engine 4.20

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Importing assets into a project is done using the import_asset_tasks() function which is a member of the unreal.AssetTools class.
A reference to the AssetTools class is created by calling the get_asset_tools() function which is a member of the unreal.AssetToolHelpers class.
The import_asset_tasks() function requires a list of unreal.AssetImportTask objects as an argument, each unreal.AssetImportTask object in the supplied list represents the import action of a single asset, and contains properties needed for the import operation.
Asset import properties are set using the set_editor_property() function which is called through the AssetImportTask object.
Available asset import properties are listed here:
https://api.unrealengine.com/INT/PythonAPI/class/AssetImportTask.html

In the following example a specified texture file is imported into the project and stored in the Content(Game) > Textures folder.
* If the folder doesn’t exist it will be created.

import unreal
AssetTools = unreal.AssetToolsHelpers.get_asset_tools()
AssetImportTask = unreal.AssetImportTask()
AssetImportTask.set_editor_property('filename', "D:\Wood_Red_A.jpg")
AssetImportTask.set_editor_property('destination_path', '/Game/Textures')
AssetTools.import_asset_tasks([AssetImportTask])

The following example imports all the JPG files from folder: D:\ into the project, stores the new assets in Content(Game)\Textures folder and saves them:

from os import listdir
from os.path import isfile, join
import unreal
dir = "D:\\"
files = [f for f in listdir(dir) if isfile(join(dir, f)) and f[-3:]=='jpg']
AssetTools = unreal.AssetToolsHelpers.get_asset_tools()

import_tasks = []
for f in files:
     print join(dir, f)
     AssetImportTask = unreal.AssetImportTask()
     AssetImportTask.set_editor_property('filename', join(dir, f))
     AssetImportTask.set_editor_property('destination_path', '/Game/Textures')
     AssetImportTask.set_editor_property('save', True)
     import_tasks.append(AssetImportTask)

AssetTools.import_asset_tasks(import_tasks)

* note that when copying and pasting a script from this example, the indentation may not be pasted correctly.

Related:

  1. Get started with Python in UE4
  2. Setting actors locations

UE4 – Python Scripting – how to start

Posted on by Oded Maoz Erell

Software:
Unreal Engine 4.20

  1. Go to:
    Edit > Plugins > Scripting
    And enable the Python Editor Script Plugin.
    * also recommended to enable Editor Scripting Utilities,
    And Sequencer Scripting plugins
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  2. Restart the UE4 Editor.
  3. Open:
    Window > Developer Tools > Output Log
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  4. Switch the command-line mode from Cmd to Python, write Python commands and press Enter to execute them:
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  5. Or in Cmd mode, write ‘py‘ with a path to a Python script file, and hit Enter to execute the script:
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Links:

  1. Scripting the Editor using Python:
    https://docs.unrealengine.com/en-us/Editor/ScriptingAndAutomation/Python
  2. UE4 Python API reference:
    https://api.unrealengine.com/INT/PythonAPI/

 

Examples:

  1. Importing assets
  2. Placing actors

V-Ray Next’s PBR’ness

Posted on by Oded Maoz Erell

Software:
3ds max 2019 | V-Ray Next

A quick test of V-Ray Next‘s PBR* workflow,
Namely designing materials while previewing them using V-Ray,
Defining the material properties using the new (to V-Ray) Metalness attribute, and using Roughness rather than Glossiness, shows good results IMO.

* It should be noted that although we got used to referring to the base-color / metallness / Specular material interface as “PBR”, it is actually a principled material interface developed by Disney animations studios.

Results are generally consistent through Blender & Cycles, Maya & Arnold, and UE4.

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Related Posts:

  1. V-Ray Next – Metalness
  2. Metal In UE4
  3. Fresnel Reflections

UE4 – Bump Map

Posted on by Oded Maoz Erell

Software:
Unreal Engine 4.21

To use a ‘Bump Texture’ in UE4, or in more geeky terms, derive Normal data from a supplied height map, use the NormalFromHeightMap Node.

Notes:

  1. The height map textured is supplied via Texture Object node and not Texture Sample, and is connected to the NormalFromHeightMap‘s Height Map input.
  2. A numeric vale is connected to the NormalFromHeightMap‘s Normal Map Intensity input to control the intensity of the resulting Normals/Bump.
  3. UV coordinates for the bump map should be connected to the Coordinates input of the NormalFromHeightMap node.

bump

Related:
UE4 – Procedural Bump Normals
UE4 – fix an inverted normal map
UE4 – Triplanar mapping

UE4 – Animated texture using a Flip-Book node

Posted on by Oded Maoz Erell

Software:
Unreal Engine 4.18

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A ‘Flip Book’ node in UE4 is the way to create an animated texture using a Sprite-Sheet.
Its very simple to use:

  1. Import a Sprite Sheet texture containing the animation frames.
  2. In the UE4 Material, Create a Texture Object node, and set it’s Texture property to be the Sprite Sheet texture you imported.
  3. Create a Flip Book node and connect the Texture Object Node to its  Texture input.
  4. Connect numeric value constants to the Flip Book node’s Number of Rows and Number of Columns inputs to set the layout of the Sprite Sheet.
  5. Connect the outputs of the Flip Book node to the wanted material inputs.

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The following example shows a way to create a custom Flip Book material to animate textures.
Q: Why would you do that???
A: Well the truth is I created it without knowing there is a built-in option, and found out about the Flip Book node right after I finished my own.. 😀
But it’s also a useful example of locating tile coordinates within a plane..

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UE4 Blueprint Delay node

Posted on by Oded Maoz Erell

Software:
Unreal Engine 4.18

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The Delay node serves as a timer that will execute the connected blueprint after a predefined time in seconds.

An example of usage could be triggering a game event at a set time after the player entered a location.
You can use random values or other expressions connected to the Duration input to create a richer and less predictable interaction.

UE4 – Enable input for a Blueprint

Posted on by Oded Maoz Erell

Software:
Unreal Engine 4.18

By default, Blueprint Actors are set not to receive player input.
* If every Blueprint would be listening to player input events it would hurt game performance.

To enable input events for a Blueprint:
In the Blueprint’s Event Graph,
Connect an Enable Input node to the BeginPlay Event,
Create a Get Player Controller node and connect it to the Player Controller parameter of the Enable Input node to set which player input events to listen to.

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Creating a camera animation in UE4

Posted on by Oded Maoz Erell

Software:
Unreal Engine 4.18

  1. Create a Camera Actor:
    Cinematics > Cine Camera Actor
  2. Create a new Level Sequence:
    Right Click the Content Browser background and choose Animation > Level Sequence.
  3. In the Content Browser, Double Click the new Level Sequence to open it in the Sequencer.
  4. press ‘+ Track’ and choose Camera Cut Track.
  5. In the camera track press ‘+ Camera’ and choose the Camera Actor you created.
  6. press ‘+ Track’ and choose Transform.
  7. Move the Time-Slider to the motion start time, move the camera to its starting position and orientation, and press the little ‘+’ button at the right of the Transform track <- + -> to set the first Key-Frame for the camera movement.
  8. Move the Time-Slider to the motion end time, move the camera to its ending position and orientation, and press the little ‘+’ button at the right of the Transform track <- + -> to set the last keyframe for the camera movement.
  9. Repeat this to create more Key-Frames and develop the camera motion.
  10. Press the Clapperboard button to open the Render Movie Settings,
    Choose the file format, frame rate, resolution, and save location and press Capture Movie.

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Related:

  1. UE4 – Playing an Animated Level Sequence
  2. UE4 – Packaging a project for Windows
  3. UE4 – 3ds max & V-Ray Datasmith workflow

 

 

 

 

 

 

 

 

UE4 – Material Fresnel Node

Posted on by Oded Maoz Erell

Software:
Unreal Engine 4.18

The UE4 Fresnel node is actually a “Facing Ratio” node (aka Perpendicular / Parallel) with some extra control.
It basically allows controlling material effects according to the incident angle the surface is viewed at, which is a hugely important feature for designing advanced material effects.

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Exponent:
The steepness of the value / angle curve.

Base Reflect Fraction:
The value at perpendicular angle.

Normal:
An option to connect World Space surface normals input to affect the output of the Fresnel node.
* Tangent Space normals must be converted to World Space by using a Transform Vector node.

Note:
A value of 1.0 for the Exponent parameter, and a value of 0.0 for the Base Reflect Fraction will produce a linear “Facing Ratio” (“Perpendicular / Parallel”) falloff blend.

Examples of different values:
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More info:
https://docs.unrealengine.com/latest/INT/Engine/Rendering/Materials/HowTo/Fresnel/

Related posts:

  1. UE4 – basic architectural glazing material
  2. Understanding Fresnel reflections