Working with Large Files in Autodesk® VIZ

• Select the geometry you want to include in an XRef file.
• Click on Insert menu, and choose XRef Designs
• Select the Convert Selected button.
• Name your file and save.

The resulting file is automatically turned into an XRef file in your scene. Your scene will render the same as before. However, to change a component of the XRef file, you will need to open that smaller file and make your changes. You can choose to have the models and materials update automatically, as soon as changes are saved to the original file, or manually on demand. Once you have existing scenes you wish to use as Xrefs, you can use the XRef Design and XRef Object tools to import geometry. This method will reduce the amount of geometry stored in multiple files on your hard drive or network.

From the Insert menu, choose Xref Designs to XRef ALL the objects in a file into the current scene at one time, or choose Xref Objects to XRef individual objects into your scene. Also, if some of your geometry is complex, to further optimize your scene you can choose the proxy object options to replace it with simpler “stand-in” objects that load and display much more quickly.

Note: If you plan on using special effects, make sure the light you use is a part of the scene and not an XRef.
Note: If you plan on manipulating the position of individual objects, use the Xref Object instead of Xref Design.
Note: XRef is also an option when dropping objects in via your Asset Manager.

Substitute Modifier
The Substitute modifier can substitute any geometry, but its main use is to substitute 3D geometry for 2D block symbols. This modifier has limitations: it can substitute only single objects, not groups or assemblies (including luminaires). How does this work? When laying our your scene, you can draw a spline box that represents the location of an individual object. For example, your scene is of a classroom and you plan to eventually fill it with multiple copies of desks and chairs which you have already created and saved. You can have a spline box marking the placement of each of those tables and chairs and then later apply the substitute modifier to each of those spline box placeholders. You can then pick from an existing object in your scene or choose an XRef object from a file.   To get rid of the object, simply remove the modifier. 

Materials
If you save your material as a highly compressed GIF with a maximum resolution of 1024 x 768 and 256 colors, you’ll speed up rendering time. In most cases, however, a resolution of 320x200 is more than acceptable (especially in tiled materials).

Lights
The larger a scene, the more lighting it requires. For example, to optimize a walkthrough consisting of many different rooms all lit accurately; use the Exclude/Include tool to exclude any objects not in the same room as those lights.

• Select a light
• Select Modify on your command panel
• Select exclude
• Select the >> button to put objects from the list at left to the exclusion list on the right.

Also, if shadows don’t have to be particularly crisp, you can change the Shadow Map size (this option is not available on ray traced lights). This value specifies how large an image VIZ generates for each shadow. To reduce the Shadow Map size parameter (see image below):

• Select the light that has the shadow map you want to modify.
• Choose the modify tab, then click on the rollout for Shadow Map Params options.
• Type a smaller value in the Size spinner (default is 512)

Display
Also, don’t forget to use Display > Hide/UnHide for your objects as you are manipulating them. This won’t help your file size, but will enable you to work more efficiently with your objects. To access this, click on the Display icon on your Command panel, and then pick from the different categories to hid or unhide your objects. Or select an object and right click to bring up your quad menu for Hide options.

Hopefully, one or more of these tips will help you become more efficient in your daily use of VIZ.