x

Search in
Sort by:

Question Status:

Search help

  • Simple searches use one or more words. Separate the words with spaces (cat dog) to search cat,dog or both. Separate the words with plus signs (cat +dog) to search for items that may contain cat but must contain dog.
  • You can further refine your search on the search results page, where you can search by keywords, author, topic. These can be combined with each other. Examples
    • cat dog --matches anything with cat,dog or both
    • cat +dog --searches for cat +dog where dog is a mandatory term
    • cat -dog -- searches for cat excluding any result containing dog
    • [cats] —will restrict your search to results with topic named "cats"
    • [cats] [dogs] —will restrict your search to results with both topics, "cats", and "dogs"

Particles are culled based on spawn position

I have a trap which spawns bullets. The bullet itself has a particle system component which is set to Auto-activate. Everything work fine except the particle culling - it is based on the spawn location, not on the actual bullet location. So if the spawn location is visible I can see the projectile effect too.

I paused the game and checked my bullets - they are at the correct location, but they are only rendered if the spawn location is visible.

Any idea what can cause this / how can I fix it?

Edit: if they are spawned when they are visible and I follow the path they won't disappear. Same particle in same location with same camera angle is invisible if it wasn't visible when it was spawned.

Product Version: UE 4.14
Tags:
more ▼

asked Feb 23 '17 at 10:48 PM in Rendering

avatar image

Elathan
426 25 27 59

(comments are locked)
10|2000 characters needed characters left
Viewable by all users

1 answer: sort voted first

Culling of particle systems is done using their bounds. Normally bounds update to include all of their particles but if you have "Use Fixed Relative Bounding Box" turned on or the emitter is a GPU sprite emitter then the bounds won't be updated. I assume that one of those is the reason it's being culled when the spawn point is not visible.

Knowing more about how your particle system is set up and how you're using would be helpful in determining exactly what's happening.

more ▼

answered Feb 23 '17 at 11:00 PM

avatar image

QSBen
413 16 15 31

avatar image Elathan Feb 23 '17 at 11:29 PM

Thanks for your answer.

It is a simple billboard emitter (not GPU). If I turn on "Use Fixed Relative Bounding Box" the problem is solved. Actually I don't really need dynamic bounds for this one so I am fine.

Btw. I used the bounds showflag - that's just amazing :D colored spheres and cubes everywhere... I also found out that the dynamic bounds are staying at the spawn location. Weird but whatever.

avatar image QSBen Feb 23 '17 at 11:53 PM

Interesting, that's kind of the opposite of what I would expect. Sounds like the bounds were not updating with the particles for some reason. But if a fixed bounds works for you then I guess that's fine.

(comments are locked)
10|2000 characters needed characters left
Viewable by all users
Your answer
toggle preview:

Up to 5 attachments (including images) can be used with a maximum of 5.2 MB each and 5.2 MB total.

Follow this question

Once you sign in you will be able to subscribe for any updates here

Answers to this question