RealFlow Houdini Plug-in

RealFlow Houdini Plug-in
Features and Tutorials
This manual describes how to use the plugins made for the RealFlow-Houdini connection, and
includes a number of tutorials on workflow.
Installer
Windows
The plug-in has an installer wizard so that users are not required to manually copy files into the
Houdini directory. The installer auto-detects which Houdini versions are installed and where. Only
Houdini 64-bit production builds are supported. In order to install the plugins for different versions
of Houdini, you will need to indicate the full path where Houdini is installed: for example
"C:\Program Files\Side Effects Software\Houdini 10.0.337\houdini\".
The wizard auto-detects Houdini versions and installation locations.
Linux
The 64-bit linux plugins can be installed as a compressed archive or as an RPM package. The archive
file (realflow_houdini_setup.tar.gz) contains the plugins for all the supported versions of Houdini,
together with an additional shell script which installs the plugins into the default Houdini
directories. Please note: You must be the root user to install the plugins correctly. If you do not
have root access, an error message will appear and the installer script (>>
install_realflow_houdini.sh) will not exist.
The RPM installer (realflow-houdini-1.0-1.x86_64.rpm) searches for the installed Houdini builds
and installs the plugins for all of the existing versions of Houdini. Uninstalling the RPM package will
remove all the plugin contents from the Houdini subdirectories.
Toolbar
The functionality of the plug-in is conveniently accessible via a toolbar and also from the SOP/ROP
levels. The toolbar is not loaded by default.
Add RealFlow toolbar.
RealFlow toolbar.
The function of the buttons, starting from left to right, is as follows:
•
RF Mesh Importer: Imports RealFlow mesh .bin sequence with the selected attributes.
•
RF Particle Importer: Imports RealFlow particle .bin sequence with the selected attributes.
•
RF SD Importer: Imports RealFlow SD scene file.
•
RF Particle Exporter: Exports particles to RealFlow SD format. The node is available at
SOP/ROP level.
•
RF SD Exporter: Exports scene geometry and camera. The node is available at SOP/ROP
level.
RF Mesh importer
RF Mesh Importer loads the RealFlow mesh sequence with the selected attributes. The syntax of
the sequence can be defined based on Houdini's script syntax. For example, a sequence like
Mesh0100001.bin, Mesh0100002.bin, Mesh0100003.bin can be set as Mesh01$F5.bin, where $F5
refers to the current frame number with the specified padding. Missing frames may report an error
or a warning notification, depending on the user setup.
Memory management and speed can be balanced via the Cache mode feature which has the
following options: Per Frame, Core Frames, All Frames. In Per Frame mode, the artist only loads the
current frame into the RAM. Core Frames holds the neighborhood of the current frame in the
memory. The core size can be dynamically set. All Frames caches the whole sequence.
Start/End frames are set automatically after a correct file path is given. Later this can be changed,
so that the plugin will only render the geometry inside the specified interval.
Frames of the sequence can be shifted, the current frame can be locked, and also the whole
sequence can be inverted.
Main Tab of the RF Mesh Importer.
Mesh Imported from RealfFlow.
Parameters:
• File Name: The name of the Real Flow mesh file sequence to read.
• Missing Frames: Specifies what should be done if the specified file does not exist on disk.
By default, if no file of the given name exists, the SOP will give an error. This can be
troublesome in a network that can’t recover from the error. In these cases the behavior
can be set to No Geometry so only a warning is posted. Note that in No Geometry mode, if
an input exists to the File SOP, it will be passed through. This allows the File SOP to
become a read-only cache.
• Scale: The resize factor of the imported mesh.
• Start/End Frame: Indicates the start and end frame of the sequence.
• Offset: Shifts the imported sequence.
• Lock Last Frame: Keeps the last imported frame displayed.
• Invert Sequence: Inverts the file sequence.
• Cache Mode:
- Current Frame: Reads the current file from the disk.
- Core Frames: Reads frames inside the ''Cache Core''.
- All Frames: Reads all frames inside the specified start/end range.
• Cache Core: The radius for Core Frames mode.
• Reload Cache: Resets cache data.
Cache Tab of the RF Mesh Importer.
Attributes Tab of the RF Mesh Importer.
•
Keep/Add/No Attributes: Mesh attributes can be loaded from the file, or can be
overridden by custom expressions.
Importing attributes like velocity and texture can be enabled independently. The Keep
Texture/Velocity option loads the original texture/velocity, and the Add Texture/Velocity option lets
the artist define custom textures and velocity attributes. The following local variables are available
inside the RF Mesh Importer node:
•
NPT
The number of points.
•
PT
The id of the current point.
•
VX, VY, VZ
Velocity vector values.
•
TEXVECX, TEXVECY, TEXVECZ
Texture vector values.
Note: For more information please see the RF Mesh Importer node help file.
Note: When you import a mesh from RealFlow into Houdini, the UV Map is applied to the mesh
if there is a gizmo texture daemon applied in the RealFlow scene.
UV applied in RealFlow with a texture gizmo over the mesh.
TUTORIAL (How to import a RealFlow mesh into Houdini)
1- There are two methods to import a mesh from RealFlow into Houdini . First, you can add it
directly from the toolbar by clicking on RFMesh Import button in the toolbar
the mesh will be allocated in the viewport.
An RF_mesh_import node will be created.
2- Double click on the node to display the inner RF Import mesh node.
Node to import the mesh.
Now you can choose the mesh sequence generated from RealFlow.
indicating where
Importing the BIN sequence.
Selecting the BIN files.
Note: Remember to note the names for BIN files. Houdini takes the default names of RealFlow as a
full sequence of numbers. You must indicate the name of the sequence and the digits that the
sequence has. Mesh$F7 will be Mesh01$F5.
3- The mesh will then be loaded in the Houdini viewport.
Mesh loaded in Houdini viewport.
4- - The second way to create the RF Mesh Import node is to create it manually by adding a
geometry node using the TAB menu.
Geometry node.
5- Double click on the geo node and delete the file node. Then a new node called rf_mesh_import
can be added using the TAB menu inside of the geo node.
Manually created RF Mesh Import node.
6- - To load the mesh sequence, follow the steps as above.
TUTORIAL (Rendering a RealFlow mesh that contains multiple fluids)
This example shows a basic approach to rendering RealFlow meshes by creating a custom Surface
SHOP Type from VEX nodes. This example describes a setup that is able to render two fluids.
1- Import the mesh sequence into Houdini. For each vertex, weight attributes are created that
represent the contribution of each type of fluid in the mesh. Using these attributes makes it
possible to render complex, multi-type fluids.
Mesh loaded in Houdini viewport.
The RealFlow mesh contains two types of fluids whose weights are represented by text_wght0 and text_wght1.
2 – On the VEX panel create a new VEX Surface Shop Type by pressing TAB.
VEX Surface SHOP Type creation
3 – Inside the VEX Surface SHOP type node create a basic shader network using the following : a
Parameter node , a ColorMix node , and 2 Water Surface nodes.
The parameter node is labeled as the first weight attribute: text_wght0. The “Invisible” flag should
be turned on. The parameter will drive the “bias” input of the ColorMix node. The ColorMix node is
responsible for blending the source materials. In this case blending will occur based on the vertex
weights. Water Surface nodes act as the inputs of the ColorMix node.
Basic shader for mixing multiple fluids.
4 – Compile the VEX code to SHOP Type. Apply your shader to the RealFlow mesh and render your
scene.
Compile the VEX code to SHOP Type.
Result of the rendering.
RF Particle Importer
RF Particle Importer loads RealFlow particle .bin sequence with the selected attributes. The syntax
of the sequence can be defined based on Houdini's script syntax. For example, a sequence like
Particle0100001.bin, Particle0100002.bin, Particle0100003.bin can be set as Particle01$F5.bin
where $F5 refers to the current frame number with the specified padding. Missing frames may
report errors or a warning notification depending on the user setup.
Memory management and speed can be balanced via the Cache mode feature which has the
following options: Per Frame, Core Frames, All Frames. In Per Frame mode you only loads the
current frame into the RAM. Core Frames holds the neighborhood of the current frame in the
memory. The core size can be dynamically set. All Frames caches the whole sequence.
Start/End frames are set automatically after a correct file path is given. Later this can be changed,
so the plugin will only render the particles inside the specified interval.
LOD (Level of Detail) is used for filtering the particles in the viewport. Complex fluid systems can be
displayed as a smaller number of guide particles in the viewport.
RF Particle Import node Main tab parameters.
Frames of the sequence can be shifted, the current frame can be locked, and also the whole
sequence can be inverted.
• File Name: The name of the Real Flow particle file sequence to be read.
• Missing Frames: Defines what should be done if the specified file does not exist on disk. By
default, if no file of the given name exists, the SOP will give an error. This can be
troublesome in a network that can’t recover from the error. In these cases the behaviour
can be set to No Geometry so only a warning is posted. Note that in No Geometry mode, if
an input exists to the File SOP, it will be passed through. This allows the File SOP to
become a read-only cache.
• Scale: The resize factor of the fluid particle object.
• LOD: The level of detail of displayed particles in percents.
• Start/End Frame: Indicates the start and end frame of the sequence.
• Offset: Shifts the imported sequence.
• Lock Last Frame: Keeps the last imported frame displayed.
• Invert Sequence: Inverts the file sequence.
• Cache Mode:
- Current Frame: Reads the current file from the disk.
- Core Frames: Reads frames inside the ''Cache Core''.
- All Frames: Reads all frames inside the specified start/end range.
• Cache Core: The radius for Core Frames mode.
RF Particle Import node Cache tab parameters.
• Keep/Add/No Attributes: Particle attributes can be loaded from the file, or can be
overridden by custom expressions.
RF Particle Import node Attributes tab parameters.
Importing attributes, like velocity, force, normal etc., can be enabled independently. The Keep
Attribute option loads the original attribute that is stored in the file, and the Add Attribute option
lets you define custom textures and velocity attributes. The following local variables are available
inside the RF Particle Importer node:
•
NPT
The number of points.
•
PT
The id of the current point.
•
VX, VY, VZ
Velocity vector values.
•
TEXVECX, TEXVECY, TEXVECZ
Texture vector values.
•
FX, FY, FZ
Force vector values.
•
VORTX, VORTY, VORTZ
Vorticity vector values.
•
NX, NY, NZ
Point normal directions.
•
NUM_NEIGH
Number of neighbors.
•
TEXVECX, TEXVECY, TEXVECZ
Texture vector values.
•
INFOBITS
Info bits value.
•
AGE
Age value.
•
ISOTIME
Isolation time value.
•
VISC
Viscosity value.
•
DENS
Density value.
•
PRESS
Pressure value.
•
MASS
Mass value.
•
TEMP
Temperature value.
• Show Bounding Box: This parameter enables a bounding box around the imported particles
as a guide geometry.
RF Particle Import node Display tab.
Viewport display properties can be set on the Display Tab. The Display type can be Points or
Particle System. The bounding box of the particles can be visualized from here as well.
RF Particle Import displayed as Points and displayed as Particles System. Show Bounding Box is enabled.
NOTE: For more information please see the RF Particle Importer node help file.
TUTORIAL (How to import RealFlow particles into Houdini)
1- To import particles from RealFlow in Houdini, you can add them directly from the toolbar by
clicking on the RF SD Import button in the toolbar
allocated in the viewport.
indicating where the particle object will be
A RF_particle_import node will be created.
2- Double click on the node to display the inner RF particle Import node.
Node to import the particles.
Now you can choose the particle sequence generated from RealFlow.
Importing the BIN sequence.
Selecting the BIN files.
Note: Please note the names for BIN files. Houdini takes the default names of RealFlow as a full
sequence of numbers. You must indicate the name of the sequence and the digits that the
sequence has. Circle$F7 will be Circle01$F5.
3- Particles will be loaded in the Houdini viewport.
Particles displayed in the Houdini viewport.
4- The second way to create the RF Particle Import node is to create it manually by placing a
geometry node using the TAB menu.
Geometry node.
5- Double click on the geo node and delete the file node in it. Then add a new node
rf_particle_import using the TAB menu.
Manually created RF Mesh Import node.
6- Follow the steps to load the particle sequence as explained above.
RF SD Importer
The RF SD Importer loads the RealFlow SD scene file.
Memory management and speed can be balanced via the Cache mode feature which has the
following options: Per Frame, Core Frames, All Frames. In Per Frame mode, you only load the
current frame into the RAM. Core Frames holds the neighborhood of the current frame in the
memory. The core size can be dynamically set. All Frames caches the whole sequence.
Start/End frames are set automatically after a correct file path is given. Later this can be changed,
so the plugin will only render the particles inside the specified interval.
Frames of the sequence can be shifted, the current frame can be locked, and also the whole
sequence can be inverted.
RF SD Import node Main tab parameters.
Parameters:
•
File Name: The name of the Real Flow SD file to be read.
•
Missing Frames: Defines what should be done if the specified file does not exist on disk. By
default, if no file of the given name exists, the SOP will give an error. This can be
troublesome in a network that can’t recover from the error. In these cases the behaviour
can be set to No Geometry so only a warning is posted.
Note: In No Geometry mode, if an input exists to the File SOP, it will be passed through.
This allows the File SOP to become a read-only cache.
•
Start/End Frame: Indicates the start and end frame of the sequence.
•
Offset: Shifts the imported sequence.
•
Lock Current Frame: Keeps the last imported frame displayed.
•
Invert Sequence: Inverts the file sequence.
On the Attributes panel the texture import and CG and object transformations can be loaded.
RF SD Import node Attributes tab parameters.
•
Texture (U, V, W): Imports uvw texture coordinates.
•
CG (Position, Velocity, Angular Rotation): Imports center of gravity attributes.
•
Object Transformations: Imports transformations applied on the objects.
•
CG Transformations: Imports centre of gravity transformations.
Note: When you select the icon
and click on the viewport to place a SD import node, an
object reference is created. It will be substituted by the original objects created in RealFlow
and contained in the SD file.
RF SD reference object substituted by a RealWave SD object.
Note: RealWave can be imported as an SD file just like an SD object.
NOTE: For more information please see the RF SD Importer node help file.
TUTORIAL (How to import RealFlow SD files into Houdini)
1- In order to import SD from RealFlow into Houdini we can add it directly from the toolbar by
clicking on the RF SD Import button in the toolbar
allocated in the viewport.
indicating where the particle object will be
A RF_SD_import node will be created.
2- Double-click on the node to display the inner RF SD Import node.
Node to import the SD files.
Now you need to choose the SD files generated from RealFlow.
Importing the SD file.
Selecting the SD files.
Note: Keep in mind that after clicking on the animation.sd file all objects contained in the sd will be
automatically created in Houdini.
3- SD will be imported into the Houdini viewport.
SD object displayed in Houdini viewport.
4- The second way to create the RF SD Import node is to create it manually by using the TAB menu
to add a geometry node.
Geometry node.
5- Double-click on the geo node and delete the file node in it. Then add a new node- rf_SD_import
- using the TAB menu inside the geo node.
Manually created RF SD Import node.
6- Follow the steps to load the particle sequence explained above.
RF Particle Exporter
The RF Particle Exporter writes the particle system data into a RealFlow .bin sequence from
Houdini. The exporter is a ROP node, also available at the SOP level. In order to add a Particle
Export node you need to be inside the SOP path of the main node of the particle object, which you
want to export as BIN files. The file name has to be set as a sequence when exporting a frame
range. Attributes for the .bin file are inherited from the Particle File Tab setup.
RF Particle Export created in the SOP Path of the node.
RF Particle Export node parameters.
•
Render: Begins the render with the last render control settings.
•
Render Control: Opens the render control dialog to allow adjustments of the render
parameters before rendering.
•
Start/End/Inc: Indicates the frames to export and the increment to generate the frames
when exporting.
•
Render with Take: Uses the settings in a particular take while rendering. Choose Current to
use the current take when rendering.
RF Particle Export node Main tab parameters.
•
Output File: The Name of the BIN file to write.
•
SOP Path: The SOP node which contains the points used to write the file. If the node's input
is connected, the SOP Path is filled in automatically.
RF Particle Export node Particle File tab parameters.
The local variables that can be used inside the node are as follows:
•
N
The current frame of the range specified. This always starts at 1.
•
NRENDER
Total number of frames being rendered.
NOTE: For more information please see the RF Particle Exporter node help file.
TUTORIAL (How to export Houdini particles to BIN)
1- Below is a scene with the objects ready to export, to illustrate how to export an SD from
RealFlow to Houdini.
Houdini particle scene to export to BIN files.
2- Add an RF Particles Export node.
3- Indicate the file where the BIN files will be saved. Then, indicate the SOP path particle node
to export.
Adding a RF Particles Export node.
4- Select the parameter for the particles.
Geometry node created. Delete file1.
5- Indicate the frames and click on the render button.
Indicate what frames will be exported.
RF SD Exporter
The RF SD Exporter writes Houdini scene data into a RealFlow SD file. The exporter is an ROP
node, also available at the SOP level. The SD scene can contain a geometry object and an
optional camera. Objects can be exported using the Objects Tab, where multiple SOP Paths can
be specified and exported with custom color data and independent Matrix modes.
Exporting an object to SD file with RF SD Export node.
RF SD Export node parameters.
•
Render: Begins the render with the last render control settings.
•
Render Control: Opens the render control dialog to allow adjustments of the render
parameters before rendering.
•
Valid frame range: Limits the rendering of frames, when set to “Render frame range” or
“Render frame range only”.
- Render any frame: Allows the renderer to render any and all frames.
-Render frame range: Only renders the frames in the range set below, but allows
the renderer to render other frames if they are referenced by in-range frames.
-Render frame range only (strict): Only renders the frames in the range set below,
and doesn’t allow the renderer to render other frames, even if they are referenced
by in-range frames.
•
Start/End/Inc: Indicates the frames to export and the increment to generate the frames
when exporting.
•
Render with Take: Uses the settings in a particular take while rendering. Choose Current to
use the current take when rendering.
RF SD Export node Main tab.
•
Output File: The name of the SD file to write.
RF SD Export node Objects tab.
•
Number of Objects: Indicates the number of objects to export. With the + button you can
add all objects you want to export. With the x button you can remove the objects you want
to exclude from exportation.
•
Apply Object Transform: Enables/disables object transformations.
•
SOP Path: The SOP node that is part of the scene.
Selecting an object to export.
•
Mode: The animation export option for the SOP. Vertex mode can export per-vertex
deformations.
•
Color: Additional information for each geometry.
RF SD Export node Camera tab.
•
Camera Path: The path for the Camera GEO level object.
The local variables that can be used inside the node are the following:
•
N
The current frame of the range specified. This always starts at 1.
•
NRENDER
Total number of frames being rendered.
TUTORIAL (How to export Houdini objects into a RealFlow SD file)
1- Below is a scene with the objects ready to export, to illustrate how to export an SD from
RealFlow to Houdini.
Houdini scene to export to SD file.
2- With several objects, you can create a geometry node which will contain the RF SD export
node. So press the TAB button and add a geometry node.
Adding a geometry node.
3- Double click on the geo node and delete the file node in it.
Geometry node created. Delete the file1.
4- Then add a new node (rf_SD_export) with TAB menu in the geo node.
Adding a RF SD Export node.
5- Indicate the name and folder where the sd file should be exported.
Where the sd file should be exported.
6- Indicate the objects to export. In this case the first object is the submarine and the second
object is the ground.
Objects to export.
7- Indicate the camera to export.
Camera to export.
8- Select the frames to export and click on the Render button to export the SD file.
Click on Render button to export.