Difference and why use both with Vellum Source and Object ?

[CinnamonMetal]

What is the difference between the vellum source and vellum object when used in a DOPNet. I find myself using both, yet it appears they both do the same thing as all I'm supplying both is the out sop path and the outConstraints path ?

[ftaswin]

The way dop was designed, you need an object of simulation type (pop, flip, smoke, vellum). Each have an initial state you can decide how the object state is when the simulation started. For most simple simulation that doesnt require additional sourcing whilst the sim running, its fine. 
 

most of the examples have a source node that set the object state only at the beginning of the sim ($ST==1). I believe it is nice for someone new to understand the logic. Source node also have a complete(ish) settings to help determine how a new items sourced should behave (life, vel, timing intervals, etc)

[CinnamonMetal]

@cloud68 You need a vellum object for the initial state of the object. Although I don't understand the purpose of the vellum source ?

You can tell the vellum object a SOP path for the initial state, so is the vellum source doing the same thing as the initial state of the vellum object ?

[ftaswin]

correct

You always need an object of some sort to start a sim, and it can start with an empty object. The most obvious use of source node is when you want to continuously emit/introduce new items throughout the sim. Think of money gun machine, or paper firework, or noodle factory type of setup/simulation. You start with something, and you keep introducing more and more money/paper/noodle during simulations.

[HM_2020]

 

On 12/17/2019 at 12:12 AM, cloud68 said:

correct

You always need an object of some sort to start a sim, and it can start with an empty object. The most obvious use of source node is when you want to continuously emit/introduce new items throughout the sim. Think of money gun machine, or paper firework, or noodle factory type of setup/simulation. You start with something, and you keep introducing more and more money/paper/noodle during simulations.

 

Any chance you know how to do something like this - Vellum:Continuous Emission with Dynamic Constraints – ZYBRAND  but with geo instead of just particles?  Or even with changing topology from a SOP?

For instance, imagine emitting the money but then having constraints connect them as they emit, so imagine more like a roll of toilet paper connected, using continuous emission. 

Or even more complex imagine in SOP carving out a curve, extruding the geo over time.  How can you tell vellum to update it (without constraints) I would like to do something like lets say have a Scarf flowing along a curve, but the scarf starts as just one poly, etc... extruding along the curve.  I would like to make that live vellum, so as it grows it can wrinkle and blow in wind , etc.

 

I am a bit confused about why you can not just have updating topology in vellum, yet continuous emission emits into ONE vellum object, in essence adding and changing the topology.  You get me?

Is it simply that under the hood its actually several objects?

Its a tough one!

 

Sorry to hijack cinnamon!

 

[CinnamonMetal]

I have some difficulty with constraints; in the following scene, I want the cube to remain together when it falls, but it is always breaking ?

 

RBDConstraints.hipnc