Ctrl + V the HoudiniEngine directory we copied in the earlier step
Note!
If you have intalled Houdini Engine for this version of unreal engine berfore you will allready have a dir called HoudiniEngine, just delete it and then paste the copied version
Gotcha
Outputs
Proxy Static Mesh
With proxy static mesh enabled houdini engine will create a proxy which will be faster to generate
Might have some artifacts
You can disable this if here
Houdini Proxy Mesh Generation >
Enable Proxy Static Mesh : On/Off
Multiple Outputs
In Houdini
Add multiple output nodes
Set the Output Index of each output to a unique value
In Unreal
With the houdini engine actor selected, open the details panel
Houdini Engine > Asset Options >
Use Output Nodes : On
This will make sure each output is used to generate an actor in UE
Unzip & copy the HoudiniNiagara folder to the …/Epic Games/UE_5.2/Engine/Plugins/FX folder in Unreal.
Example
Houdini
Create a particle/point setup that oyu wish to use in Unreal
add a Labs Niagra ROP node
Save to disc
Unreal
Import cache
In the contnet browser, drag and drop the .hbjson file we saved from Houdini.
Add a Niagara System
In the content browser, make sure that Show Plugin Content is enabled
Select add New system from selected emitter(s)
In the dialog that popped up make sure that the Library filter Library only is unchecked.
In the asset type filtering, click Parent Emitters
In the Uncategorized section select Houdini Niagare Basic
click the + icon and then finish.
Note
You could also an empty system and then add the Houdini Niagare Basic emitter later.
Setup the system
Double click to enter the niagara system
On the HoudiniNiagaraBasic overview node there are 3 places we need to reference our houdini point cache
Note
We can hold ctrl to select multiple attr on the HoudiniNiagaraBasic node and they will populate and be editable in the selection widget on the right hand side.
Select
Emitter Update > Spawn Particles from Houdini Point Cache
Particle Spawn > Sample Spawned Houdini Point Cache
Particle Update > Sample Houdini Point Cache
In the selection widget expand the three sectins until you see Houdini Niagara entry. Here we will drag and drop our imported point cache
Set Loop Duration
We can se how many seconds our cach is by double clicking the houdini point cache.
The we can hold shift + RMB click on the Max Sample Time
Then we go back to our niagara system, select the Emitter Update
In the Selection tab expand Emitter Update > Emitter State > Life Cycle >
The paste the copied value to the Loop Duration
Set Lifetime
Select Particle Spawn on then expand Particle Spawn > Initialize Particle > Point Attributes >
Set lifetime to 0.1
since a particle is spawned every frame we do not need this to be longer.
Particle Attributes
Select the HoudiniNiagareBasic node’
in the parameters panel expand Particle Attributes to see which attributes are accessible.
Lets set the color
On the HoudiniNiagareBasic click the + icon on the right side of the Partcle Update
start typing ‘col…’ select General > Color > color
With the added color module selected we can see that we can edit the color in the selection panel.
Since the color value is RGBA and the houdini color is a vec3 we need to use the Scale Color (a vec3) to set the color.
On the right side of the scale color klick the down arrow and start typing ‘hou…’ then select Particles Houdini Color
Lets set the Size
we are using a sprite renderer so we will set the sprite size.
Click the + icon on the right side of the Particle Update
start typing ‘spr…’ then select Scale Sprite Size
in the selection panel change the Scale Sprite Size > Scale Sprite Size Mode to Uniform
Because there is a difference in units we need to multiply the houdini pscale with a large number (lets start with 100) to get the correct size
Click on the arrow on the right side of Uniform Scale Factor and start typing ‘mul…’ select Multiply by Float.
Set the A value to 100
click on the arrow on the right side of B and start typing hou… select Particles Houdini Pscale