Hi,

Is there anyway to adjust the velocity of the particles without overriding forces.
Basically I am a bit confused about how the attribute v is calculated in the DOP network.

Basically I think I understand the concept of the v attribute and how defining it will force that particle to that particular velocity. But I wonder if there is a way to define the velocity and then allow that velocity to be influenced that other forces to get the final v. Rather than like now it seems once you set v, that's it, that's all that particle velocity will ever be.
or maybe I should never set v I should always set forces?

I haven't worked with DOPs but I put down a network and looked at the available nodes:

There's a Velocity Impuse Force node, but you mention ‘particle’ so I see also that there is a particle velocity node as well.

Either of these wouldn't help you accomplish what you need?

My mistake, after I set up a simple hip file I notice the forces DO affect the velocity appropriately so it must be a mistake in my other set up that is overriding some forces…..In certain ways thank for the brainstorming it point me to where I should be looking at.

On thing to remember is to not assign a value to velocity. Instead modify the existing value by an amount. Also the placement of the Wrangle in the network does matter so you may want to do your final velocity manipulations after forces are applied, or before…

AVIOD THIS:DO THIS:

Enivob
On thing to remember is to not assign a value to velocity. Instead modify the existing value by an amount. Also the placement of the Wrangle in the network does matter so you may want to do your final velocity manipulations after forces are applied, or before…

AVIOD THIS:

v@v  = 0.1;

DO THIS:

v@v *= 0.9;

Indeed I learn this the hard way…But is quite logical once you think about it. I was basically creating my own orbital velocity for the particles but I ended up applying the same network as a wind force. I was getting the result I wanted modifying the velocity but the wind force plays a lot better down the road when I add other forces to the simulation. I basically agree with you, even though it works I feel is better to avoid assigning a value to velocity.

I also noticed (as an alternative) that you could create a POP Wrangle with this:
The POP Solver will recognize the new attributes and update @v based on the v@targetv value that you specify. The higher the @airresist, the more it will immediately move towards your target vector. I got this from opening up the POP Wind hda.

jlim
I also noticed (as an alternative) that you could create a POP Wrangle with this:

@airresist = 1;
v@targetv = {0,0,1};

The POP Solver will recognize the new attributes and update @v based on the v@targetv value that you specify. The higher the @airresist, the more it will immediately move towards your target vector. I got this from opening up the POP Wind hda.

Yes, what you are doing is basically creating a wind force on the POP wrangle. I decided to do it on the popvop because the network was a bit more complex. But indeed it seems that a good approach is to use wind force (or targetv) rather than v. Of course they will be exceptions but as Enivob says it seems that as a general rule assigning a value to v should V avoided (Sorry for the silly joke)

The force is added to the velocity. The particle is advected by the velocity (in other words, v is added to P). Force is reset to 0.

I find it easier to control when adding to the force. That way it doesn't accumulate over the duration of the sim (which is what happens when you add to v since obviously it doesn't get reset to 0 at the end of each timestep).