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creo496
05-14-2002, 06:33 PM
Hello

I'm working on a medical animation and I'm trying to simulate red blood cells flowing through a vein. I have tried using the Effect "Curve Flow" with particle instances of the red blood cells. However I can't seem to get enough control over their rotation and movement in general. I've tried using the Rotation Options under the Instancer Replacement but I'm not getting the results or the control I want. I can't find very much documentation on the Rotation Options.

So any ideas, recommended tutorials or known documentation would be great.

Thanks
creo496
svenip
05-14-2002, 07:12 PM
you could try to use a field (maybe turbulence) and then set the rotation of the instancer to force. this will let the particles rotation be driven by the force.
svenip
05-14-2002, 07:19 PM
like this
creo496
05-14-2002, 09:09 PM
Hey svenip

Thanks for the tip! That looks like its going to work.

creo496
svenip
05-14-2002, 10:35 PM
here's the one for better/finer control

go to the AE of your particleShape. add a general dynamic attr. under the new tab type in a name for the attribute (i tend to use the particlename+myRotate)(blood.myRotate). then select vector as the data type. because rotation is given by 3 values it's a vector. select per particle array because we want to have each particle a different one. hit ok.
after that right click on the new attribute and select "runtime expression". this because we want to change to rotation over the time. now we have so many options to write a custom expression for that. this is just a very simple one.

blood.myRotate = <<frame/20,frame/20,frame/20>>;

then go to the rotation attributes of the instancer in the AE and
in the select box for rotation choose your new attribute.

now you have only a start. go to the expression and write it more customly and randomly. a good tip is to use smoothstep function together with noise or simple random.

just take a look in the mel commands help. you will find a good explaination of these functions.
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