A digital asset stores its contents in a number of different pieces of data called sections. Each section is named and contains an arbitrarily sized piece of data, often textual. Each section is like a file embedded inside the definition, and Houdini uses specially named sections to store the node contents, list of parameters, etc. You can embed your own data into a digital asset by putting it inside a section.
Any parameter in Houdini that references a file can also reference a section
inside a digital asset. For example, if car is an object-level digital
asset and the section is named "texture.jpg", you can reference
that texture with opdef:/Object/car?texture.jpg. Note that hou.readFile()
also supports this opdef: syntax.
By moving files into digital asset sections, you can build self-contained digital assets that can be distributed via a single hda file.
Note that section names may contain '/'.
Methods
name()
→ str
Return the name of this section.
Note that is is not possible to rename a section, but the following function will emulate renaming:
def renameSection(section): '''Rename a section by removing it and creating a new one. Return the new section.''' new_section = section.definition().addSection(new_name, section.contents()) section.destroy() return new_section
definition()
→ hou.HDADefinition
Return the digital asset definition containing this section.
contents(compressionType=hou.compressionType.NoCompression)
→ str
Return a string containing the contents of this section.
You can optionally specify a compression type, hou.compressionType, to decompress the contents.
Raises hou.OperationFailed if a compression type is specified and the contents are not compressed by that type.
def saveSectionToFile(section, file_name): '''Given a section, save it to a file.''' section_file = file(file_name, "w") section_file.write(section.contents()) section_file.close()
size()
→ int
Return the number of bytes in the contents. This method is a shortcut
for len(self.contents()).
setContents(contents, compressionType=hou.compressionType.NoCompression)
Set the contents of this section to the given string. A section may contain binary information, like bgeo files, images, etc.
You can optionally specify a compression type, hou.compressionType, to compress the contents. Note that you must specify the same compression type when reading the contents back to decompress them.
See hou.HDADefinition.addSection() for an example of how to create a section from a file on disk.
destroy()
Remove this section from the HDA definition. You can also remove a section
with hou.HDADefinition.removeSection(), and this method is equivalent
to self.definition().removeSection(self.name()).
Only remove sections that you explicitly added. Do not remove the special sections that Houdini uses to store the contents of the digital asset definition, or Houdini will generate errors or strange side effects.
To add a section, use hou.HDADefinition.addSection().
modificationTime()
→ int
Return the time when the section was last modified. This time is returned
as a POSIX timestamp, such as is returned by time.time().
>>> hou.nodeType(hou.cop2NodeTypeCategory(), "colorwheel").definition() <hou.HDADefinition of Cop2 colorwheel in /opt/hfs9.5/houdini/hda/OPlibCop2.hda> >>> definition = hou.nodeType(hou.cop2NodeTypeCategory(), "colorwheel").definition() >>> definition.sections().keys() ['VflCode', 'DialogScript', 'VexCode'] >>> section = definition.sections()['VflCode'] >>> section.modificationTime() 1177535169 >>> import datetime, time >>> datetime.datetime.fromtimestamp(section.modificationTime()) datetime.datetime(2007, 4, 25, 17, 6, 9) >>> time.ctime(section.modificationTime()) 'Wed Apr 25 17:06:09 2007'