UE4 – Python Scripting – how to start

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/
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UE4 – Bump Map

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.

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UE4 – Animated texture using a Flip-Book node

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 itsĀ  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.. šŸ˜€
But it’s also a useful example of locating tile coordinates within a plane..

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UE4 – Enable input for a Blueprint

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

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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Create a richly colored metallic surface in UE4

Software:
Unreal Engine 4.18

One of the optical properties of many metallic surfaces is changing it’s color slightly as the surface viewing angle changes.
This effect can be simply created using a FresnelĀ node and a color-ramp texture.

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  1. Create a metallic material (metallic value of 1.0).
  2. Use an image editing software to create a linear colorĀ ramp texture (gradient) of the color change per viewing angle from left to right. like this example for a golden metal, and import it to your project.
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  3. Add the ramp texture to the material Blueprint, and connect it to the material Base Color Input.
  4. Create a Fresnel node and set its Exponent value to 1.0 and its Base Reflect Fraction to a value of 0.0 so it will provide a linear angle blend value.
  5. Connect the Fresnel node’s output to the UVs input of the ramp texture node.
    * the reason the Fresnel node can be providing both the X and Y texture coordinates is that the texture’s Y dimension provides the same color for all values anyway.

Note:
When the Metallic property of an Unreal Engine material is set to 1.0, the material automatically simulates the metal’s color fading to white at parallel surface viewing angle (the sides) like it should.
So using a Color Ramp Texture like in this example creates an amplified effect.
* Simply put: You don’t have to have the Color Ramp fade to white on the right side of the texture..

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