• | **Need to know exact time in milliseconds for the "number" property**
on Apr 19, 2009 at 6:39:10 pm |

I need to synchronise emitters' emissions to pieces of music with known tempos, so I therefore need to know what pre-set milliseconds values are used per "number" unit between each particle's emission for the "number" property so that I can make the best approximation for the tempo I want. My videos look wrong in timing so far, and the reason why I haven't been able to synchronise in the "preview" window is that the frame rate rendered is, as expected, always a little quicker than what I see in preview. Also, when using a circle or elliptical emitter, exactly how much pre-set time elapses per "number" unit for each round of the ellipse/circle when "emit at points" is selected? (I also need to synchronize elliptical emitters with music of a known tempo).

Thanks so very much again, Alan.

• | **Re: Need to know exact time in milliseconds for the "number" property** on Apr 19, 2009 at 7:04:47 pm |

Sorry, I must add that I also need to know the time elapsed between each particle emission per "number" unit "per pixel" for area emitters too, since I need to synchronise area emitters also.

Thank you so much,

Naveen

• | **Re: Need to know exact time in milliseconds for the "number" property** on Apr 20, 2009 at 4:08:05 am |

I don't think I have an answer to this one. I might be able to figure it out if I looked at the code long enough, but there are a lot of variables.

- framerate of the project

- if any of the particle types in the emitter use a non-zero number variation

- if you're using the "use old number calculation" option

Here's what I suggest you do:

1) load the "blank" emitter library

2) adjust the "number" property to 1

3) determine the time between each particle's creation

Then you can use this for your own calculations.

Alan.

http://www.wondertouch.com

• | **Re: Need to know exact time in milliseconds for the "number" property** on Apr 27, 2009 at 2:07:21 am |

I've found, am I right, that the project frame rate does not affect the actual time in seconds between particle creation, or the rate per second of movement of the emission point when using "Emit at points". Is this correct? Can I ask what the "old number calculation" is? Do both calculations have a linear relationship with respect to time in all cases in terms of both number % and number value? If so I can do the tests myself. But if not (my preliminary tests in the preview stage window suggest not in some cases), it seems too daunting for me to figure out the mathematical relationship! I would need the actual calculations (I can read copy-and-pasted C++ if the variables have understandable names) for point,area,ellipse and line, so I can figure out the exact times I'm getting in each case.

But surely if one of the methods is linear, you would have some constant values you're using (I've found that changing the project frame rate does not affect the actual time between particle creation, right? And I'm not using any number variation)? If so, the specific values I am pursuing, which would be constant throughout your program, but not necessarily explicitly defined:

Point: number of particles per second per number % per number value (e.g. 0.0005)

Area: number of particles per second per number % per number value per pixel (e.g. 0.000000000001)

Ellipse/Circle: number of rotations per second of the emission point around the ellipse/circle when using "Emit at points" per number % per number value (e.g. 0.00000002)

Line: number of repetitions of the emission point moving along the line when using "Emit at points" per number % per number value (e.g. 0.00000002)

Thanks so much,

Regards,

Naveen Chawla

• | **Re: Need to know exact time in milliseconds for the "number" property** on Apr 28, 2009 at 1:49:27 pm |

Ok I've found that the number % is not linear, but the number value is, and that the "new" number calculation is simply more accurate than the "old" one. Also, at 1%, at value 1, it is 65 seconds exactly for one particle, at any project frame rate, therefore "1/65 particles" per second per number value at 1%. Does this sound right? I'll post more info as I find it. Can I please know the mathematical relationship for the number % value?

• | **Re: Need to know exact time in milliseconds for the "number" property** on Apr 28, 2009 at 3:40:11 pm |

That last result was for point emitters. Ok so here are my results (new number calculation), at number 1%, and they apply for all project frame rates. The values that I was pursuing in my post before last, concluded from the results, are shown in brackets:

Point: 1 particle per number unit every 65 seconds exactly, at any frame rate (therefore value I wanted: 1/65)

Area: 1 particle per number unit every 21.5 seconds exactly per 100 x 100 pixels, at any frame rate (therefore value I wanted: 1/21.5/10000)

Ellipse ("Emit at points"): 1 rotation of the emission point per number unit every 65 seconds exactly, at any frame rate (therefore value I wanted: 1/65)

Circle ("Emit at points"): 1 rotation of the emission point per number unit every 65 seconds exactly, at any frame rate (therefore value I wanted: 1/65)

Line ("Emit at points"): 1 run along the line per number unit every 65 seconds exactly, at any frame rate (therefore value I wanted: 1/65)

Now all I need from you is the mathematical relationship for the number % value, which I have found not to be linear.

• | **Re: Need to know exact time in milliseconds for the "number" property** on Apr 30, 2009 at 2:56:13 pm |

Alan, perhaps my question got lost in the big posts. Are you able to tell me the mathematical relationship of the number % property versus actual rate, which I have found not to be linear. Or if you want to save time, to copy and paste the code and I'll (try to) decipher it?

• | **Re: Need to know exact time in milliseconds for the "number" property** on Apr 30, 2009 at 8:09:08 pm |

It's just not that simple, and I don't have the time or patience to work through it all right now to give you an answer.

At some time in the next few months I may be looking at this code anyway and can possibly answer then, but right now I just can't answer.

Sending or posting the code is not an option.

Alan.

http://www.wondertouch.com