[Archived - Lexique] Local Vs World Particles, and specifically wondering about Gravity Point

Posted by “Lexique” on April 14, 2023.

@4u​ , thanks for your response and for looking at my mesh! I didn't realize that I could use the sink plane in a local environment. And I think that the reason I thought that is because when I tried it before, the sink plane didn't align with my axes so I assumed that it wasn't working. But I can see that it is just an error with the particle viewer, it also has the same trouble as the gravity>point. The sink plane particle viewer assistant is also out off to an angle like my picture above of the gravity>point. But I can see that in fact it is working correctly as long as I don't turn on the particle viewer and try to go by that.

I have just created some raindrops as if they are running down a window. I have turned on random acceleration. i was getting it too fast, and then your message came in and you mentioned about turning to speed to zero. For some reason I never thought to try to put it all the way to zero. That did help.

The random acceleration seems to necessitate the sink plane as I cannot so easily determine how long to make the lifetime using this advanced feature.

Posted by “4u” on April 14, 2023.

Found your mesh, the node IS in the middle

So for a box shape emission the only position you need is to lift it off the floor, centre is like 0,0,1.6

Then to say fill the space I'd make the box size 3,3,3 which fits with a particle max size of .1

For other products I've made similar I turn speed off 0,0 and use gravity to move them in the direction you want eg falling down

I'd set speed to 0, 0 size 0.02, 0.1

Direction is irrelevant because speed is off but I'd normally make it random

Gravity for falling is 0,0,-.1

And don't forget to add an sink on or below the floor.

Posted by “Lexique” on April 14, 2023.

Thank you @4u​ I have a number of your boxes - you're very inspiring! 0,0,0 is right under my feet. x left-right, y front-back, z up-down. But it seems that often in imvu stuff, it's y that runs up-down. But every math class I've ever taken puts z up and down lol. I have never had a problem with my meshes being "off kilter" - only this "gravity>point". And actually I figured out that as long as I make sure that the particle is in "local space", the axes for the gravity>point runs the same as the product. However the issue is that the particle viewer for the gravity point (the little pink sphere) is still working in world space - I guess it is? So I just have to ignore it. Maybe if my product was aligned y-up there would be no issue. Thanks for your offer to pm you I do have lots of questions about all sorts of things, I'll try to just ask one at a time!

Posted by “4u” on April 14, 2023.

If the node isn't in the middle, make/get another mesh :P.. When working wit boxes I find it easiest to start with a sphere 0,0,0 in size so a dot.

and position that in the centre of the box, and then you have your coordinates as to where that is, which you can use for the box coordinates and then just increase its size. Your gravity is pulling to the left then up and then backward, seems weird but it could be node related or an effect your trying? Same with the box shape being different sizes.

I've made a lot of those boxes for tictok people, if you want to pm me exactly what your attempting and mesh link I can give you a better reply knowing what the issue is.

Posted by “Lexique” on April 14, 2023.

Here's my last response, @miaka618​ - I have just now looked at both of the videos you both sent me. I had watched some of the butterfly video already, and in fact I was live watching the learning session 12 and even asked a question. :-). I hit the subscription button and I intend to watch your videos on other things! I am indebted to @jazzKat​ for your videos creating and importing fbx files. I have a lot more to learn on the meshing frontier. For particles, my final frontier is the advanced random acceleration and displacement - I think if used minimally, they could create a nice fluttering and flying effects for birds and butterflies, etc, especially I'm thinking linear random acceleration Thanks to both of you for your responses and help.

Posted by “Lexique” on April 13, 2023.

One thing I've noticed is that every engine seems to display things a bit differently. What I see in Studio is not necessarily what I see on the iPad app, which can be a bit frustrating.

Posted by “Lexique” on April 13, 2023.

wow, thank you @jazzKat​  and @miaka618​ ! I feel like I'm in the midst of imvu celebrities! I may have already watched that butterfly video? But I'm going to check it out in case I haven't yet. I've watched most particle videos, have already watched yours, jazzKat.

I understand what you are saying regarding the 2D planes always facing the viewer, I wasn't even thinking about that or I would have not even asked that question. I just simply need to add the rotation to my animation texture.

I intend to revisit this parabolic effect in future products as I can see some real potentials. I can see it looks nicer when it is a whole swoosh of particles rather than just one, because the whipping effect around some invisible point seems kind of weird. However, I moved the parabolic point outside of my display cube and I liked that better. I am going to work more with the angle of my bird group during the cycling animation to produce the essence of turning around as you mentioned. It would have been easier if I'd just done one bird as the particle instead of a group, and I might do that. Anyway I count this as a learning product!

I include it here so you can see what I have at this point... please don't cringe!

https://www.imvu.com/shop/product.php?products_id=63275657

Posted by “jazzKat” on April 13, 2023.

Oh nice!

Posted by “miaka618” on April 13, 2023.

@[jazzKat] it can be done. This learning session explains particle to point where the particles spin around a center point.

​

https://create.imvu.com/articles/studio/imvu-studio-learning-session-12-particles-and-new-features/

​

And thank you for sharing my butterfly video. It is also an example of animated particles which gives the illusion of 3d.

Posted by “jazzKat” on April 13, 2023.

Not sure what causes that issue with the particles getting 'stuck' but yes, had that as well and it seems to fix itself saving/closing/restarting as you mention.

So far as I understand the 2d plains that form the basis of particles always face the viewer so they can't turn around in of themselves. But... if you watch @miaka618​'s animated particle vids you can see she gives that impression by animating the texture assigned to the particle (see the 'coin' video - think this was the IMVU sessions) https://www.youtube.com/watch?v=VJTYX4zsIRs

If you mean you want to make the particles whirl around like a tornado, not sure that can be done.

Posted by “Lexique” on April 13, 2023.

oops sorry, I accidentally answered lol. @jazzKat​ ... I have found two errors. At least I think they are. One is, I didn't realize that I'd turned on world space again when I took the above pictures.

The first one is an error in the particle viewer - when I turned on local space, the gravity > point changed to have the same axis as the product, which I didn't think it did before. HOWEVER, the point in space that the particle viewer is manifesting is as if the world space is on. So the point does not correctly manifest the gravitational system in when using local space.

I had an error where the effect seemed a bit extreme and I could not get it to change. So eventually I saved and got out of the program and got back in and then it was different. So something got "stuck" or some cache didn't get cleared or something. But exiting out and starting over did not change the location of the gravitation point viewer (the little pink wire sphere).

The second error is more of a personal request maybe. is that when the particle whips around the gravitational point, the particle does not turn around. So in essence, now it is going backwards. This is ok if the particle is uniform in shape but not if it has an actual front and back, like a group of birds!

Posted by “Lexique” on April 13, 2023.

Thank you for your response, @jazzKat​ ! I have watched your two videos. I am currently watching the creator in residence particle video as well, looking for more information on this.

Posted by “jazzKat” on April 13, 2023.

Yep, gravity does give the appearance of odd behaviour so you don't want to watch it necessarily but rather the longer red particle orientation indicator. If that points UP as its normally understood, but the particles drift down that means either gravity has a negative value, or, the particle effects speed isn't sufficient to over come a positive gravity value. It can definitely be mind bending trying to figure out which value needs adjusting for sure!

Posted by “Lexique” on April 13, 2023.

Thank you @jazzKat​, I will. I have watched all of the imvu youtube videos, but sometimes it's hard to go back and sort through the videos to find one little detail like this. I don't think I've watched specifically yours on particles so I will do that.

You can see from my pictures that I am working with the particle viewer on, otherwise I couldn't figure out anything at all. But I have determined that the y axis is the vertical axis and the z and x axes are twisted at seemingly a 45 degree angle from this arbitrary point in space. My accessory is attached at the root, and so the origin coordinates seem to calculate from the root (i.e., the avi's feet, essentially), at least for the types of origins that I've tried (this is a box), so I find it curious that the gravity point is so different.

Posted by “jazzKat” on April 13, 2023.

Have a look at this https://www.katsbits.com/codex/particles-imvu-studio/ and this https://www.katsbits.com/codex/toolkit-accessory-particles/ but for here, turn on the 'Particle' widget and see the direction the red arrow points - that indicates the emissions direction, which can change depending on the 'root' the particle is attached to.