[Request] Render GPU particles when emitter is not visible

Development Asset Creation FX
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Currently when emitter of GPU particles is not in screen space, it stops emitting particles. While I understrand it is probably due to optimization, it would be nice to be able to specify this behavior on per emitter basis.

I have run into this probablem today while trying to make flowing sand, on pretty narrow space, and it just look odd, when particles suddenly stop being visible.

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Hi Lukasz,

Ignore my previous response if you already saw it. I have an answer for you now.

When you set the TypeData to GPU Sprites, you may have noticed this message appear in the Preview window:

“WARNING: This particle system has no fixed bounding box and contains a GPU emitter”

The missing bounding box is what causes the particles to disappear when the emitter is off-screen, since GPU particles require a fixed bounding box. To enable this, in Cascade, click in the black background (not on the emitter), and in the Properties tab search for “bounding”, click the checkbox for Use Fixed Relative Bounding Box, then up on the toolbar, click the Bounds button to see the bounds on screen. The size of the box can be modified by expanding the dropdown in Properties and modifying the Min/Max.

In the level, you will now notice that the particles will only disappear when the edges of the bounding box are off-screen.

I hope that helps!

1 Like
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Hi Lukasz,

I am not currently aware if there is any reason that GPU particles must function this way, but I have reported the issue to our rendering team.

Thanks

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Thanks for that, exactly my issue!

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I have this same thing happening to me. I have a fireplace in my scene and it is my only source of lighting and when I look away from the fireplace the fire goes out and everything is dark.

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^^
Thanks!

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Thank you! Fixed my issue too.

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awesome! Someone should think about something to prevent people searching for the same missunderstanding over 3 years :smiley:

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i need this to be on screen at all times, to create a cascading lava effect.
this is a scene i put together

Though not demonstrated in the video, When i play in the level the lava stops creating new particles when i look away from it, even with the fixed bounding box set incredibly high

it seems to be dependent moreso on the camera being able to view the actual collision of a particle to occur in able to keep rendering that specific particle without deleting it

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i found a bit of an answer as to what’s going on at 8:14 of this video