Maxwell's MXS Reference feature provides a powerful tool for helping to overcome the 32-bit memory limitation of SketchUp. Essentially, an MXS Reference is just the path to a Maxwell MXS (i.e. Maxwell Scene) file, which is read and inserted into the model at render time only, by the render engine itself. This, as opposed to geometry directly contained in, and exported from the SketchUp model.
In the SketchUp plugin, an MXS Reference is represented as a Component, to which the path to an MXS file has been attached. To enable visual placement of the reference within the SketchUp model, the plugin reads the specified MXS file and builds a proxy set of bounding boxes describing the geometry it contains. When the model is rendered, rather than export the proxy geometry, the plugin writes the MXS path, instead. This allows for working with hundreds or thousands of instances of complex pieces of geometry, without significantly slowing down SketchUp, and without using more memory than necessary.
Inserting MXS References
To insert a new MXS Reference, click the plugin's Insert MXS Reference menu item or toolbar button:
A file browser dialog will be shown, prompting for an MXS file from which to build the reference; once a file is chosen, the plugin will then prompt for an insertion point (this works interactively) in the SketchUp model. Once the reference has been placed, it will appear as a new Component composed of a set of bounding boxes:
Rendering the model, the bounding box geometry will be replaced with that of the referenced MXS file:
The MXS Reference may be copied and transformed the same as any other component:
Such that rendering again:
When loaded into the render engine, the first instance of the MXS Reference will require memory sufficient to hold all of the geometry it contains, and the external files (textures, etc) it references. Further copies, however, will consume very little memory, since they will be exported as instances of the first reference.
Creating MXS files for referencing
As of plugin version 3.0.11, it is possible, with a licensed plugin running in SketchUp Pro, to create MXS files for referencing directly from within SketchUp, by using SketchUp's File > Export > 3D Model command.
Note that unlike SketchUp, Maxwell does not store referenced files (i.e. textures, MXM files, IES files, etc) inside of MXS files, so it is necessary to ensure that all files referenced by the MXS file be available where it is used as an MXS Reference. Also note that while appropriate for the creation of MXS files to be used for referencing, this method of export (i.e. File > Export > 3D Model) is not recommended for use by Maxwell Render Suite customers, since it bypasses the plugin's Ruby code, which takes care of making sure camera, environment, output, and other settings have been synchronized.