[Super Beginner] Touchdesigner’s “UnrealEngine Plug-in Samples” Explained — TOP

4 min readSep 25, 2021

Operators that can be handled by TouchEngineComponent

In TouchEngineComponent, there are three main Touchdesigner operators that can be used for Input/Output.

It’s
These three things!

TOP
CHOP
DAT

You can use SOPs, COMPs, etc. in Tox, but you can only be directly involved in the above three.

So, since each of them is processed differently in UE4, let’s take a look at them.
This time, we’ll look at the TOP!
Click here to watch the video!

The inevitable blueprinting system

It’s similar to how you would connect operators in Touchdesigner.
You will connect each node for each process.

Since BP is something you can’t avoid, I’d recommend doing the official UE4 tutorial, but

But don’t worry!
You don’t have to do it this time!

Because
Basically, we’re going to start from scratch.
We’re going to do something like that.

But this time, since we are looking at the contents of Samples, we will use the originally created BP.

How do I open a blueprint?

As an example, let’s take BP_TE_UESample02_SimpleTexture.
Then, go to the Detail panel -> Edit Blueprint -> Open Blueprint Editor in the upper right corner.
Then, you will see a screen like this

This is the Blueprint editor.

I’ll skip the details, but I will explain the TouchEngine Component node!
I’ll try to explain the TouchEngine Component node!

Event nodes (red ones)

All the buttons are available in the bottom right corner of TouchEngineComponent.
Just click on it!

Set Inputs

When some kind of CHOP, TOP, or DAT is input to TouchEngine Input,
it runs!

Get Outputs

when the TouchEngine Output is acquired!
This is used so much! Important of Importants

Function nodes (blue ones)

Set TouchEngine Input

By specifying Input Name and Value, you can put values into Input with UE4 types.

Get TouchEngine Output

If you specify the Output name, CHOP/TOP/DAT will be entered as the value in the value as the UE4 type.

What is the type of TOP in UE4?

I’ve been using the term “UE4 type” for a while now.
What I mean by this is this…

You can’t use Touchdesigner’s TOP in its original form in UnrealEngine!

You need to change it to a form specific to UnrealEngine.

This is like a translation.
If you compare Japan to Touchdesigner, and the U.S. to UnrealEngine.
“In Japan, everyone understands the Japanese phrase “onaka suiteru.
But what if you said it in America?
What if you said it in the U.S.? It would be considered mysterious English!

In the U.S., you need to translate into English, the language that is understood in the U.S.
If you say “I’m hungry,” you will get the message.

Type conversion is similar to this translation process.

Now then, what type of TOP will it be?

That’s for next time!

And I’m not going to pretend like it’s the next episode of an anime!
So, I’ll announce it!
Drum roll, come on!

Texture2D
That’s it!

Woohoo!

If you’ve never used UE4 before, you may not be familiar with this…
It’s a type that can be used as a texture.

Anyway!
TOP is Textue2D
This is important!
If you remember this, please push good button to prove it (laughs)

It seems that UE4 also has a crazy amount of other familiar Int, Float, String, Name, etc. Scary!

Switch TOP is in use!

Look UE4Sample04_SimpleBlendCubeTexture
Here you can see how the two TOPs (Texture2D) are being blended together.
This is where Touchdesigner’s Switch TOP is being used.