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Houdini 8 transition guide

Welcome

Houdini 8 to Houdini 9 transition guide

Welcome to Houdini! This guide describes changes between Houdini 8 and Houdini 9, as well as ways for Houdini 8 users to make Houdini 9 more comfortable.

This guide is not exhaustive, but it contains the big changes and points to consider as you transition over to the new release.

Viewing and selection

The mouse buttons for viewing have changed

  • Space + MMB is now track/pan

  • Space + RMB is now dolly/zoom.

  • RMB now always shows a context menu.

    You must hold Space to dolly/zoom with RMB.

We strongly recommend you spend some time trying make the transition. It’s very useful in the network editor, for example, to be able to pan with the middle mouse button and zoom with the mouse wheel while keeping the right mouse button available for the context menu.

Houdini 8 users having a hard time with this can switch the mouse buttons back by setting the HOUDINI_MMB_PAN environment variable.

Selection changes

  • Houdini now has a single selection, instead of remembering a separate selection in every network.

  • Houdini now supports selection-action in addition to action-selection. Houdini 8 users may need to pay attention to whether they have a selection when they start using a tool, because Houdini will try to use it.

  • The Select tool S lets you select objects, geometry, particles, or dynamics prior to using a tool.

  • Because RMB now always shows the context menu, press Enter or Shift + RMB to finish a selection.

Panes

Tabbed panes

  • You can now have multiple tabs inside a pane, each containing a different pane type, similar to tabbed web browsing.

  • Drag and drop pane tabs to reorder them.

  • Right click a pane tab to change its pane type. Click the Add button to get a menu of pane types to add.

Panes follow selection

  • The context of the panes follow the selection unless you pin them.

  • It’s very useful to have a parameter pane and network pane that follow the selection, and then add tabs containing pinned panes looking at important nodes and networks.

  • You can still get the Houdini 8 pane linking behavior by right-clicking the Pin icon to show a list of linking options.

Shelf

Tool shelf

  • The shelf contains commonly used tools. Many tools on the shelf eliminate the need to manually create one or more nodes.

  • Many shelf tools have alternate behavior when you Ctrl-click them. For example, the geometry primitives appear at the origin instead of waiting to be placed. When you Ctrl-click a light or camera on the shelf, it uses the current view.

  • Each icon on the shelf represents a Python script that runs when you click it. You can right-click a tool and edit it to see its script.

  • Shelf tools appear in the Tab menu in the viewer.

  • You can change the size of icons in the shelf using options in the drop down menu.

  • You can create new shelf tools by right-clicking the shelf, or by dragging nodes/assets up to the shelf.

Tools everywhere

  • The Tab key menu shows scripted tools.

  • You can create a tool on the shelf and choose in which contexts in shows up in the tab menu.

  • Tab menu type-ahead is now limited to the currently open menu. If you open a sub-menu and start typing, only the items in that sub-menu will match.

    Be careful not to accidentally open a sub-menu before you start typing if you don’t mean to only search that sub-menu.

  • You can map any tool (asset or script) to a hot key, making it easy to execute scripts and create nodes.

UI tips

  • To control the brightness of the UI, choose Edit > Color Settings. Gamma 1.2, Brightness 0.7, Contrast 1.1, Saturation 0.8 are a good starting point if you wnat to tone down the brightness.

    The Saturation setting affects the icons as well and is one way to tone back or enhance the colors.

  • To change the size of the UI elements, choose Edit > Preferences > General User Interface and set the Global UI Size.

    You can also use the HOUDINI_UISCALE environment variable to scale the UI (a value of 100 is the normal size).

  • If the shelf is taking up too much room, click the bar along its left side to collapse it, or click to open the shelf tab menu and use the Display Tools as sub-menu to change the size of the shelf icons. Try Text or Small icons and text for a very compact shelf.

  • To color the panes to show their context, similarly to Houdini 8, choose Edit > Preferences > General User Interface and turn on Color Pane Headers with Network Contents.

  • To “bookmark” a network: press Ctrl + T to create a new network tab and pin it.

  • The Link As Parent option in the Pin menu gives you the old “ducks” behavior where this pane will follow one folder up from the other linked panes.

  • You can still press P in the network editor to embed a parameter editor.

Network editor

Network navigation mouse buttons

  • Space + MMB is now pan

  • Space + RMB is now zoom.

  • RMB now always shows a context menu.

    You must hold Space to dolly/zoom with RMB.

  • Using a wheel mouse you can pan with MMB and zoom with mouse_wheel without having to hold Space.

  • You can set the Environment Variable HOUDINI_MMB_PAN to revert to the old button order.

Easier wiring

  • Selectable wires are on by default. Right-click a wire to see a list of commands for that wire.

  • Wire snapping and halos give you bigger click targets. Once you start wiring, you can click anywhere on the destination node to finish the link (the entire node highlights blue).

  • Use Ctrl + LMB to always drag a node, no matter where you “grab” it (even on a connector or flag). This is especially useful for VOPs.

New path gadget

  • Right-click path gadget for context menu. Press Ctrl + L to type a new network location.

  • To jump to a different top-level network, press and hold on the first item in the path gadget.

Modeling and SOPs

  • When the viewer is not at the scene level (when you're selecting geometry, particles, or dynamics), the default is now to show other objects “ghosted”.

    You can use the icon on the viewer toolbar to switch to the Houdini 8 modes of show all or hide others.

  • You can now grab the rotation handle anywhere for free rotation. The “ball” defined by the rotation rings is darkened to make this clearer.

  • The display and render flags are now a single flag on SOPs. Click to move the combined flag. Ctrl-click a node’s display flag to set the render flag there. Ctrl-click the display flag to merge the flags again.

  • The node with the display flag is now indicated in the network by a blue circle behind the node. The node with the render flag has a purple ring.

Create in context

The create objects menu on the operation controls toolbar (above the viewer) lets you choose where the shelf tools will put new creation nodes.

Right click or press and hold on the icon to change the mode.

Create objects: New creation SOPs are added inside new geometry objects.

Create in context: Houdini 8 style: new creation SOPs are added inside the current object.

The create objects menu also has a Keep original objects option.

When this option is on, Houdini will use Object Merges to combine object geometry (for example, when you use curves to create a Loft surface) instead of actually moving the nodes into the same object.

Viewer

  • Viewers no longer follow the pane context. A 3D viewer will not spontaneously change to a CHOP viewer, compositing viewer, etc.

    To revert back to pre-Houdini9 viewport behavior, change the tab’s pane type to Context View.

  • Increased visual separation between viewports.

  • New viewer toolbar (across the top of the viewer), viewport menus (in the top right corner of each viewport), and render tools (at the bottom of the toolbox on the left side of the viewer) replace most of the functionality found in the old bottom toolbar.

  • Space + B to mix/max a viewport

    (In Houdini 8 this was Space + T).

  • Oblique view of the grid is now default view.

    Space + H

    Home view

    Space + A

    Show all

    Space + G

    Show selected.

Shading

Render properties

Render Properties replace many default parameters on Nodes.

To add properties to the selected node(s), choose “Edit Rendering Parameters” from Gear menu in the parameter editor.

Materials

  • New shader architecture: VOPs inside shaders (SHOPs) inside materials. Materials can contain multiple shaders (such as a surface shader and a displacement shader).

    Materials can also contain Property nodes that add certain render properties to the material (such as displacement bounds).

    You can promote parameters from shaders and property nodes up to the material just like building the UI of a digital asset.

  • Material palette lets you load materials from galleries on disk. You can drag a material from the palette onto objects or selected faces to assign the material.

Rendering

New features

  • New PBR renderer settings in the mantra render node. Easy to use and play with.

  • New volume primitive for rendering of volumes.

  • New Environment light casts light into the scene from a surrounding hemisphere or sphere.

  • Mantra now supports multi-threading and multi-segment motion blur.

Rendering and SOHO

  • During rendering, properties are translated into IFD, RIB, etc. output by a Python mapping program using the SOHO API.

  • New mantra render node to support SOHO. Old Render drivers using the old ifd generation mechanism may still work you should move all methods to materials, new Mantra nodes and SOHO.