Unreal Engine – Oded Erell's CG Log

UE4 – Package a Project for Windows

Posted on June 13, 2019June 13, 2019 by Oded Erell

Software:
Unreal Engine 4.21

Basic steps for packaging a simple UE4 project for Windows:

Package settings:
Open the Project Settings window:

In: Project > Description
Set the project’s details and thumbnail:
> The Project thumbnail will apear in the UE4 Editor browser.
> Thumbnail image must be a 192 x 192 resolution PNG
In: Project > Maps & Modes
Set default level (Map) for the project:
In: Project > Packaging
Choose build configuration
> For final distribution choose ‘Shipping‘:
In: Project > Supported Platforms:
Make sure Windows is selected:

Note:
If the project folder is located within a deep folder structure, there might be packaging errors because of long file paths.
Adding a Quit command:
Select the FirstPersonCharacter Actor and enter editing mode.
In the Event Graph blueprint, add an Escape key press event node,
And connect it to a Quit command node.

Creating the game package:
Choose:
File > Package Project > Windows > Windows (64-bit)
And select an output folder.

A folder named “WindowsNoEditor” will be created,
And inside it will be the game executable along with code and assets folders.
This package can be renamed and copied to other locations.

UE4 – Connect a Directional Light to an Atmospheric Fog effect

Posted on May 31, 2019June 1, 2019 by Oded Erell

Software:
Unreal Engine 4.21

UE4‘s Directional Light mimics sun lighting and shadow fairly realistically,
And the Atmospheric Fog visual effect produces a realistic clear sky background that includes the sun’s disk image in the sky.
> The Atmospheric Fog produces a result similar to an implementation of a Preetham physical sky model in common rendering software.

Combined together, these two elements can produce an effective day-light system,
But inorder for this to work the sun’s direction should be controlling the time of day simulated by the Atmospheric Fog.

For the Directional light to control the Atmospheric fog:
In the Directional Light’s details, under light, expend the settings and enable:
Atmosphere / Fog Sun Light

Note:
There is a limitation to this setup’s realism because the sunlight’s color shouldn’t be pure white, but rather yellowish, to orange, depending on the time of day (you can find tables of the sunlight’s color temperature for various time of day on the web)
There is no problem setting the sun’s color, but the problem is that it causes additional coloring of the Atmospheric Fog which isn’t needed since it already is simulating the sky’s color correctly.
The result of this limitation is that we can see a sunset sky with a white sunlight which is wrong.
I didn’t find a workaround for this yet, can’t find a way to set the Atmospheric Fog‘s sun vector without connecting it to a Directional light and can’t find a way to make the Directional Light‘s color not affect the Atmospheric Fog‘s color.

Update:
It seems this limitation can be overcome by disconnecting the Atmospheric Fog from the Directional Light and using the Atmospheric Fog Object’s rotation to control it.

Directional_light_Affect_Atmo_Fog

UE4 – Enable complex collision for models

Posted on May 31, 2019May 31, 2019 by Oded Erell

Software:
Unreal Engine 4.21

By default UE4 uses fast simplified convex collision shapes to calculate collision for static mesh actors.
This means that the player or projectiles wont be able to path through holes, openings or doors in the model.

To set complex (concave) collision for a static mesh model:

In Static Mesh editing window, in the details pane, under Collision:
Set Collision Complexity to: Use Complex Collision As Simple

This example shows the default behavior for a model that has an opening, neither the projectiles nor the player can pass:

In this example collision for the model was set to Use Complex Collision As Simple:

UE4 – Python – Importing assets

Posted on April 9, 2019April 10, 2019 by Oded Erell

Software:
Unreal Engine 4.20

Untitled-1

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.

Get started with Python in UE4

UE4 – Python Scripting – how to start

Posted on April 9, 2019April 9, 2019 by Oded Erell

Software:
Unreal Engine 4.20

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

Links:

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

UE4 – Bump Map

Posted on December 7, 2018June 3, 2019 by Oded 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:

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

UE4 – Animated texture using a Flip-Book node

Posted on March 8, 2018March 10, 2018 by Oded Erell

Software:
Unreal Engine 4.18

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

Import a Sprite Sheet texture containing the animation frames.
In the UE4 Material, Create a Texture Object node, and set it’s Texture property to be the Sprite Sheet texture you imported.
Create a Flip Book node and connect the Texture Object Node to its Texture input.
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.
Connect the outputs of the Flip Book node to the wanted material inputs.

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..