Unreal Engine Archives

I’ve just learnt about a nifty mechanism to change parameters on a material node in Unreal Engine. The niftyness lies in the fact that when we convert static values in the material editor into parameters, which then become the equivalent of public variables that are accessible from other parts of UE4. It sounds way scarier than it is, let me show you how it works in detail.

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I’ve always been marvelling at all the little moving background items in video games. Most trees, grass, plants and such foliage appears to move subtly. How do they do that? Perhaps it’s a wind node? Surely that’ll eat up huge amounts of resources.

I just found a computationally cheaper trick to do this, namely by adding this effect to the plant’s material, thanks to a video by MetalGameStudios. It suggests that we can do this in two ways, both of which are described below. In either case, open the material of your object to proceed.

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I’ve just figured out how to setup keyframe animations in Unreal Engine, and thought I’d make a note of it before I forget. I made the animation above a little while ago by “poking around”, but it wasn’t as smooth as I liked it to be. I think I’ve found the missing bits now, so here’s how it works. From what I gather, Unreal Engine calls Keyframe Animations “Cinematics”. They’re a little tricky to setup, because the whole engine is built for so much more, but in principle we need to:

• create a new Level Sequence
• create a Cinematic Camera
• add the camera as a Track to the Sequencer
• create keyframes for/with the camera
• add a Camera Cut Track
• export your animation as a video or image series

I’m going to create a camera animation like in the demo above, but any regular mesh object and Actor can be animated, including lights and their properties, so this process is not limited to cameras. However you need at least one camera to render out the sequence, at least that’s my goal here. The process will be different if you’d like to trigger the sequence from within a game, which is not in the scope of this article.

Let’s see how to do this step by step.

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Following on from my earlier article about referencing a Blueprint from another Blueprint, Unreal Engine has another interesting way for inter-object communication. Sometimes we need to reference more than one object, say when press a button and want several objects to react, all in their own different way. Imagine pressing a button and a light goes off, a particle effect gets triggered and several enemies get spawned. Event Dispatchers can do that, and here’s how we can use them.

In this example I’ll have a Switch object, and a Lamp object. When we press the switch, it’ll send out a message to which the Lamp (and other objects) can react. Each object can implement the function and execute different code. I’ll only show the abstracted Lamp code here for brevity, from which I’m sure you’ll understand the gist.

Sadly the terminology “dispatcher” is a little confusing. At least to me, it suggests that an event is dispatched (i.e. sent), whereas in reality the dispatcher is actually the listener rather than the sender. Hence the dispatcher needs to be setup on the event that needs to react. A real-world dispatch worker doesn’t work that way (thanks code people for confusing us non-coders).

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I’ve just found out how to change values for Morph Targets on objects in Unreal Engine via code. This will come in handy when any attribute needs to be updated either as a result of user input, or via automation. Here’s the basic workflow:

• know the exact name of the Morph Target
• add a Set Morph Target node in Blueprints
• populate it with the name of the morph
• give it a value (between 0 and 1, equivalent to 0% to 100%)

Here’s a small example that continuously changes my Genesis 8 character from Basic Female into Olympia. While not particularly useful in itself, it illustrates how a parameter change can trigger a morph.

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When you start a new Blueprint Class in Unreal Engine, there’s this weird white ball that shows up in the centre of the viewport. I believe it represents the Default Root object. Trouble is, there’s no obvious way to get rid of it, even when you add a mesh object to your Blueprint. For a troubled and easily confused beginner like myself, I don’t even know what question to type into Google to get an approximate answer.

In this article I’ll show you the simple solution to the problem. Here’s the ball I’m referring to:

Even with a Static Mesh in my scene, that ball persist. I can’t even select it.

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In my quest to take a look behind the scenes of how game engines work, I’ve decided to take a closer look at the Unreal Engine, more specifically UE 4.22.3. I had installed it a few weeks ago but other than launch a template or two, I didn’t do anything else with it. After my recent deep dive into Unity, I thought this would make for a nice comparison writeup.

Here’s how I experienced the first 24 hours with Unreal. I’ve even added a video at the end to show you a level that I’ve built. For this review I’ve been following this tutorial series by Paul Kind. He’s a wonderful teacher!

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