UE4 Blueprints – Spawn Actor Transform Note..

Unreal Engine 4.24

Short version:
When Spawning new actors via the SpanActor Blueprint node, initial transform must be supplied to the SpanActor node, and not defined in the spawned Actor Class’s Blueprint.

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Just found out the hard way, that when you spawn an Actor using the SpawnActor blueprint node, the transform data connected to the SpawnActor node is actually applied after the actors Construction Script and BeginPlay Event.
This means any transform you will try to apply in the spawned Actor’s Blueprint will be overridden and therefore not work.

UE4 – First Person Projectile Overlap Event

Unreal Engine 4.24

Had some frustrating time not understanding why doesn’t the FirstPersonProjectile Actor doesn’t “play ball” and generate Overlap Events when hitting my bad guys..
It turns out I had to change its collision (sphere) component’s collision settings to overlap dynamic objects (see image):
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UE4 Material Blueprint Shortcuts

Unreal\n Engine 4.24

Some useful Unreal Editor Material Blueprint shortcuts:

  1. Hold 1 and LMB Click to create a 1D Constant node:
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  2. Hold 2 and LMB Click to create a 2D Constant node:
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  3. Hold 3 and LMB Click to create a 3D Constant node:
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  4. Hold S and LMB Click to create a Scalar Parameter node:
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  5. Hold V and LMB Click to create a Vector Parameter node:
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  6. Hold L and LMB Click to create a Lerp (Linear Interpolate) node:Annotation 2019-12-26 005653
  7. Hold M and LMB Click to create a Multiply node:
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  8. Hold A and LMB Click to create a Add node:
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  9. Hold T and LMB Click to create a Texture Sample node:Annotation 2019-12-26 010504
  10. Hold U and LMB Click to create a Texture Coordinate node:
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  11. Just press C to create a comment:
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More UE4 Material Editing posts

UE4 – Enable complex collision for models

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:



Vector Parameters in the UE4 Material Blueprint

Unreal Engine 4.18

UE4 Material Blueprint Numerical Vector Parameters / Constants and Colors are one and the same, which makes perfects sense, since in computer graphics colors are in fact 3D vectors, RGB quantities being equivalent to XYZ spatial dimensions (4D with an Alpha channel)

But take note that when setting the Vector values in the color picker you can’t set negative values, and when doing so through the Details window in Default Value you can.

* You can create 3D Vector Constants by clicking the background while pressing 3