SC Operator

 

“SC” is the new ShapeCollision operator for thinkingParticles which is meant to replace the “old” ShapeCollision operator. This all new rigid body solver offers many advantages over the old one and uses the latest methods and algorithms to calculate rigid body dynamics, providing faster, more accurate, more efficient and more flexible performance than the “old” ShapeCollision operator.

To keep backward compatibility with older scenes and files, the old ShapeCollision is still available from the Dynamics Menu and it produces the exact same results, as it did in previous versions.

We recommend using this new SC operator instead of the “old” ShapeCollision       The new SC operator offers you the following benefits

• Support of multiple Joint types
• Enhanced Multi-Threading/Multi-Core support
• Specifying Contact Type is no longer needed
• Enhanced Solver Algorithm for better full frame sampling
• Increased Overall Speed
• High Frequency Jittering has been reduced significantly
• Voxel Debug Mode added 

As a testament to the power that comes with the SC operator, it was successfully used in the 2010 blockbuster movie 2012 and was instrumental in creating the destruction effects in the various shots of the movie.

While it is possible to use multiple Shape Collision operators in a DynamicSet, it is highly recommended that you use as few operators of this type as possible. The memory requirements are huge and they increase with each addition of that operator type.          

ON - (Bool) This input data stream determines whether the operator is considered 'on' or 'off.' You can connect other operators to this input channel such as a Bool Helper to activate/deactivate the whole operator.

Time - (Time) This input data stream is used to define the local time for the operator when the user wants to override the default system time.

Floor Node - (Node) This input data stream is used to specify through a node helper for example a 3D mesh as a floor collision object. A floor object is automatically treated as immovable with an infinite mass.

Voxel Grid - (Integer) This input data stream is used to override the Voxel Grid that is used on the selected particle Group. This value is normally set within the selected Group's Dynamics rollout.

Edge Samples - (Integer) This input data stream is used to override the Edge Samples value that is used on the selected particle Group. This value is normally set within the selected Group's Dynamics rollout.

Optimize - (Bool) This input data stream is used to override the Optimize check box setting that is used on the selected particle Group. This value is normally set within the selected Group's Dynamics rollout.

Elasticity - (Scalar) This input data stream is used to override the Elasticity value that is used on the selected particle Group. This value is normally set within the selected Group's Dynamics rollout.

Dynamic Friction - (Scalar) This input data stream is used to override the Dynamic Friction value that is used on the selected particle Group. This value is normally set within the selected Group's Dynamics rollout.

Static Friction - (Scalar) This input data stream is used to override the Static Friction value that is used on the selected particle Group. This value is normally set within the selected Group's Dynamics rollout.

Size As Mass - (Bool) This input data stream is used to override the Size as Mass check box setting within the Particle Group of Controls.

Floor Voxel Grid - (Integer) This input data stream is used to override the Voxel Grid spinner value in the Floor Group of Controls within the Shape Collision Operator.

Floor Optimize - (Bool) This input data stream is used to override the Optimize check box setting within the Floor Group of Controls within the Shape Collision Operator.

Floor Elasticity - (Scalar) This input data stream is used to override the Elasticity spinner value within the Floor Group of Controls within the Shape Collision Operator.

Floor Dynamic Friction - (Scalar) This input data stream is used to override the Dynamic Friction spinner value within the Floor Group of Controls within the Shape Collision Operator.

Floor Static Friction - (Scalar) This input data stream is used to override the Static Friction spinner value within the Floor Group of Controls within the Shape Collision Operator.

OPT Face Threshold - (Angle) This input data stream is used to override the Face Thresh. spinner value within the Shape Collision Floor Node.

OPT Edge Threshold - (Angle) This input data stream is used to override the Edge Thresh. spinner value within the Shape Collision Floor Node.

OPT Bias - (Scalar) This input data stream is used to override the Bias spinner value within the Shape Collision Floor Node.

OPT Max Edge Length - (Scalar) This input data stream is used to override the Max Edge Len. spinner value within the Shape Collision Floor Node.

OPT Preserve Smooth Boundaries - (Bool) This input data stream is used to override the Preserve Smooth Boundaries check box setting within the Shape Collision Floor Node.

OPT NumFaces - (Integer) This input data stream is used to override the Off Under Faces spinner value within the Shape Collision Floor Node.

Velocity Friction - (Scalar) This input data stream is used to override the Velocity Friction value that is used on the selected particle Group as it interacts with the Floor Node. This value is normally set within the selected Group's Dynamics rollout.

PHY Collision Iteration - (Integer) This input data stream is used to override the Collision Iteration spinner value within the Physics rollout of the Shape Collision Operator.

PHY Contact Iteration - (Integer) This input data stream is used to override the Contact Iteration spinner value within the Physics rollout of the Shape Collision Operator.

PHY Deactivation Time - (Scalar) This input data stream is used to override the Deactiv. Time spinner value within the Physics rollout of the Shape Collision Operator.

PHY Velocity Threshold - (Scalar) This input data stream is used to override the Velocity Thresh. spinner value within the Physics rollout of the Shape Collision Operator.

PHY Rotation Threshold - (Angle) This input data stream is used to override the Rotation Thresh. spinner value within the Physics rollout of the Shape Collision Operator.

PHY Activate All - (Bool) This input data stream is used to override the Activate All check box setting within the Physics rollout of the Shape Collision Operator.

Particle - (Particle) outputs the current particle information for the colliding particle. Use this to modify specific particle properties.

Collided - (Bool) this output data stream will return true whenever a collision is happening. In all other non-colliding situations, the output will report false as the value.

Collision average Position - (Position) provides the current interpolated collision point.

  Collision averaged Normal - (Normal) outputs the interpolated normal of the calculated collision point.

Frozen - (Bool) outputs the frozen status of the particles as determined by and within the Physics Rollout Menu . When particles are considered “frozen” or “inactive”, this value will be true. When particles are actively moving, this value will return false.

Double Star Output ** behaves like the Top-Level Initiator outputs, this outputs activate connected nodes for evaluation. It is important to understand that all connected nodes will be evaluated. However, as this is a secondary Initiator output, it can not be combined with the Top Level Output at the same time. The main rule still applies: Never use 2 Initiators on the same node or wiring

Number of Collisions - (Integer) holds the total number of all collisions that happened for a particle. A collision may happen multiple times, especially with sliding objects (surface - surface). Note, this is a secondary Initiator output that can not be combined with the top level Initiator outputs at the same time. Either the Top-Level will be active or the low level department but not both at the same time.

Coll Index - (Integer) outputs the current index number of the collision. This might be used to get the current progress of the collision evaluation. Collision index can become as big as the Number of Collisions value, if this is reached the collisions are done.

Coll Particle A - (Particle) outputs the particle A of the collision pair. This output is always evaluated before particle B!

Coll Particle B - (Particle) outputs particle B of the collision pair.

Coll Floor - (Bool) when a collision with the floor object happens, this output will be set to True.

Coll Position - (Position) outputs the real world position Collision point.

Coll Normal - (Normal) outputs the normal of the calculated collision point.

Coll Position A - (Position) outputs the collision position of Particle A in local object space.

Coll Position B - (Position) outputs the collision position of Particle B in local object space.

The Shape Collision operator is used to control all true shape collision dynamics in thinkingParticles.

Group - this drop-down list selects the particle collision partners for the floor or inter-particle collision.

All Physics based parameters are set and controlled within the particle group itself. Select the relevant particle group in the particle group tree view to access the dynamic properties of a particle group.

Deflector - is used to choose the deflector objects. Important: those objects will be treated as unyielding, all the time, regardless of their local physics settings. One application would be to use recorded particles as deflectors.

Size As Mass - Activate this check box to enable an automatic mass calculation that is based on the size of the particle. For example, a particle with a size of 2.0 will be treated as 2 Kg.

Voxel Grid - This spinner defines the number of cubic subdivisions to wrap the object's outer boundaries within.

Optimize - Activate this check box to enable the parameters found in the Rollout Menu. The face count of the colliding meshes will be automatically reduced. This face reduction is only done “internally” for the collision objects and not for the rendering mesh. This option may speed up the dynamic simulation enormously. However, if overdone the results may be inaccurate.

Elasticity - Use this parameter to control the bounce value between the floor↔particle collisions. Higher values will make the particles lose less energy per bounce. Be aware that values greater than 100 will create extra energy and the particles will gain energy with each bounce.

Dynamic Friction - This spinner sets the friction (you can also think of it as “power loss”) between particles and the floor when they impact with each other. Please note that this power loss ONLY happens on impact.

Static Friction - This spinner defines the friction between particles and the floor when they are in contact (sliding). Higher values will make the particles slide less.

Velocity Friction - This spinner defines the relative speed difference between two particles. A slower particle will force a faster one to slow down. This can be used to simulate viscous substances like molasses.

Show Voxels - check this option to enable Voxel debug mode. When on, Voxels will be visible in the view port as small red dots.

Initialized Only - when checked, initialized Voxels will be shown as green dots. Initialized Voxels are those Voxels involved in the final collision detection to find the closest surface point of a colliding partner.

Direction - when checked yellow dots appear on the surface of the colliding objects indicating the direction of collision based on the nearest Voxel in space.

thinkingParticles allows you to record particle dynamics. It is always a good idea to use this feature whenever a simulation seems to be perfect for the job. Recording the particles as they bounce around will make life easier at a later rendering stage. Playback from hard disk is also usually much faster than calculating the solution each time you play back the particle collisions.

Select Record File - Click this button to bring up a standard Windows Save dialog. Any legal name and path can then be specified to save the recorded particle simulation.

Simulate, Play, Record - These buttons are fairly self-explanatory. The Simulate button turns the recorder into playback mode and will play back the recorded file on hard disk as you scrub the 3ds Max frame slider in the view ports. The Record button will switch the recorder into record mode. With the record button pressed, clicking the Play button on the 3ds Max time line will start the recording and simulation of the particle dynamics. After the last frame has been reached, the recording automatically stops and turns into Play mode to show you the results.

Active Time Segment / Range - This is a standard 3ds Max control that lets you choose whether you want to record the entire particle animation, or just a specified range of frames as defined within the two spinners.

Redraw Views - when checked, the 3ds Max view ports will be updated while simulating. Depending on scene complexity it might be a good idea to turn of View Updates while simulating.

This rollout is responsible for adjusting the degree of optimization for the particle collisions.

Off Under Faces - If an object that is being sent to be optimized has fewer faces than the threshold value set in this spinner, it will not be processed for optimization and ignored. This does not affect it's participation within the simulation, it simply removes it from the optimization routines.

Face Thresh - This spinner sets the threshold angle used to determine which faces are collapsed during the optimization process. Low values produce less optimization but better approximations of the original shape. Higher values improve optimization, but are more likely to result in faces that render poorly as you get more degenerate triangles. (see Bias below for information on how to control this).

Edge Thresh — This spinner sets a different threshold angle for open edges (those that bound only one face). A low value preserves open edges. At the same time you can apply a high Face Threshold value to get good optimization.

Bias — This spinner's value helps eliminate the skinny or degenerate triangles that can occur during optimization, which in turn can cause simulation and rendering artifacts. Higher values keeps triangles from becoming degenerate. The default of 0.1 is generally considered enough to eliminate the skinniest triangles, while a value of 0.0 turns the Bias setting off.

Max Edge Len — This spinner specifies the maximum length beyond which an edge cannot be stretched when optimized. When Max Edge Len is 0, it has no effect. Any value greater than 0 specifies the maximum length of the edges. Along with Bias, this control helps you avoid creating long skinny faces while optimizing.

Preserve Smooth Boundaries — Optimizes an object and maintain its smoothing. When turned on, allows only faces that share at least one smoothing group to collapse.

Collision Iteration - This spinner sets the number of sub-steps to be used to estimate the real collision point of colliding objects. The lower this number, the faster the simulation will run. However, lower values would also mean less accurate results. In most situations, you can keep this value between 5-10, while in exceptionally complex scenes, you can try to set a value as high as 30 to get more accuracy.

Contact Iteration - This spinner defines the number of sub-steps to be used between colliding objects to create a “contact” situation. Face to face contact is one of the most complex situations to handle for the dynamics engine. Increase this value to get more realistic simulations.

Deactivation Time - This spinner defines the time-slot in which a particle is surveyed to determine whether it is actively moving due to dynamics or simply performing a stupid “dynamics dance” as it comes to rest. If a particle falls into this time-slot and it's speed or rotational value is equal or below the ones defined, it is considered sleeping or frozen. Lower values will freeze the particles much faster. This spinner works in concert with the two spinners below it (Velocity Thresh. and Rotation Thresh.).

Velocity Threshold - This spinner sets the minimum speed an object needs to fall below to become treated as frozen or inactive. Be aware that other objects interacting with a sleeping one may change this status when the impact creates a velocity higher than this value.

Rotation Threshold - This spinner sets the minimum rotational speed and object needs to fall below to become treated as frozen or inactive. As is the case with the Velocity Threshold, be aware that other objects interacting with a sleeping one may change this status when the impact creates an angular velocity higher than this value.

Activate All - This check box will “wake up” frozen fragments after they have been deactivated either by Velocity Threshold or Rotational Threshold. This setting can be helpful when working with fragments, since frozen particles don't respond to space warps.