PDA

View Full Version : Instancing only works at origin?



alexoctagon2009
08-23-2013, 09:50 AM
Hi

I've had my first go at instancing and I'm having what's probably a really silly problem. I've got an emitter and I want to instance an object to the particles and I've done this OK. However, I want the emitter to be towards the back left of my scene. But when I move the emitter away from the origin, the objects then offsets themselves away from the particles, it's like the object isn't parenting itself to the emitter. So, at the moment, I can't see how to do my effect away from the origin. Can anyone help me please?!

Cheers,
Alex

bazsa73
08-23-2013, 11:47 AM
Strange indeed because I just did a test scene and it works fine. I'm on LW11.5 win64.
Did you parent the object you want to instance to the emitter? I guess you did.
Because I just tested it and if the object to be instanced is parented to the emitter gets strangely offseted.
UNPARENT! :D

JohnMarchant
08-23-2013, 12:02 PM
I believe the instances are always orientated to the center. If the origin instance is not in the center then all others will be offset by this amount from the center. As bazsa73 said probably best to unparent. Not had much experiance with particles and instances.

wyattharris
08-23-2013, 01:24 PM
Something like this rocket contrail? If so I can look it up when I get home.

http://youtu.be/mrGo0856bB0?t=1m16s

tcoursey
08-23-2013, 02:09 PM
Strange indeed because I just did a test scene and it works fine. I'm on LW11.5 win64.
Did you parent the object you want to instance to the emitter? I guess you did.
Because I just tested it and if the object to be instanced is parented to the emitter gets strangely offseted.
UNPARENT! :D

If I understand your issue with parenting you may need to check the WORLD/LOCAL coordinates as I remember. (I'm not in front of the computer to check) You can have the item parented (or not if you wish) but the correct options in the instancing dialog need to be checked/unchecked.

tcoursey
08-23-2013, 02:11 PM
Something like this rocket contrail? If so I can look it up when I get home.


Cool video!

Triodin
08-23-2013, 05:44 PM
If I understand your issue with parenting you may need to check the WORLD/LOCAL coordinates as I remember. (I'm not in front of the computer to check) You can have the item parented (or not if you wish) but the correct options in the instancing dialog need to be checked/unchecked.

This was my issue with instancing the first time I was messing with it. I think in 11.6 it should default to Local Coords, it seems like we're all wired that way :)

alexoctagon2009
08-29-2013, 09:49 AM
Sorry everyone, I haven't got this worked out yet, this is what I mean...

OK, forget the emitter. I've just modelled a sphere and put it in the scene.

Go to instance tab, add instancer, then in the instance Generator panel add object, type=polygons, 6 instances, which all appear randomly around the original model.

When I move the sphere, the instances all start offsetting themselves. I want them to stay in the same positions around the sphere, like they are parented to it if you see what I mean.

I can't see any way of choosing parenting or world coordinates to sort this out.

I've probably missed something really obvious...?

tcoursey
08-29-2013, 09:54 AM
Not sure that you will be able to do that with ONE object. You could copy the object and reference the copy and it should work fine.

wyattharris
08-30-2013, 01:05 PM
OK, forget the emitter. I've just modelled a sphere and put it in the scene.

Go to instance tab, add instancer, then in the instance Generator panel add object, type=polygons, 6 instances, which all appear randomly around the original model.

When I move the sphere, the instances all start offsetting themselves. I want them to stay in the same positions around the sphere, like they are parented to it if you see what I mean.

I can't see any way of choosing parenting or world coordinates to sort this out.

I've probably missed something really obvious...?
Man you had me stumped for a bit. I knew I'd done this before.
Anyway the best way I can describe what your example does is parent a parent. Not technically correct but same principle. You are generating instances based off of what it being instanced so when the original object is offset that value is getting calculated twice.

Try this.
1. Add a sphere and a ground plane.
2. Add the instance generator to the ground plane.
3. Set the sphere as the instanced object.

Perhaps the problem though is that you have to do this with one object. As tcoursey said I don't think that would be possible. I'm looking at your original request and comparing it to this one. I'm trying to see how they relate but not seeing it. Feel free to correct my assumptions and I'll try again.

Edit: Are you parenting the original object to the emitter? Don't do that. The object should stay put unless you want the instances to move based on the objects movements.

bazsa73
08-30-2013, 01:25 PM
Hello everyone,
This is what I wanted to explain. Alex parents the object to the instance generator. That is wrong. When one is doing so and the instance generator is translated the
instances are receiving strange offsets. This has nothing to do with local/global whatever coordinates. I hope my explanation makes sense.

dwburman
08-30-2013, 06:35 PM
116723

I usually leave the objects being instanced at the origin and just turn them off in Scene Editor (unchecking the A column), so the off-origin thing doesn't matter for me. The Local vs. World thing does take care of that problem, but it's a setting in the instance generator panel, not the general Layout setting.

It's probably best not to parent the item being instanced to the instance generator or to use it as the instance generator itself.

The illustration I uploaded would probably be a little more clear if I had the grid turned on.

bazsa73
08-31-2013, 02:44 AM
We explained this thoroughly :D

alexoctagon2009
09-02-2013, 05:00 AM
You certainly did explain it thoroughly, I knew this was something silly. I didn't actually apply any parenting, it just automatically chooses world coordinates to default. If this is changed to local then its fine. As you have said, it's better to not do this with one object really.
Anyway, thankyou so much for your help everyone!