Softimage SDK Programmer's Guide > Customizing Softimage using the SDK > Building and Deploying Customizations > Add-on Packages >

# Limitations

Here are the areas where there are known limitations with add-ons that you should be aware of:

- Shaders

- Installing Add-ons to the Workgroup Location

- Uninstalling Add-ons

- Installing an Add-on of an Older Version

## Shaders

- To access shaders from a workgroup location, the shader (alone or in an add-on) needs to be installed in the workgroup, and not installed locally in the user location.

## Installing Add-ons to the Workgroup Location

- The workgroup path can actually specify many paths which are separated by semicolons. For example:

  \bob\wkg1;\jill\wkg2;\lucie\wkg3

  Installing an add-on to the workgroup location installs it in the first available workgroup location (in this example, \bob\wkg1)

## Uninstalling Add-ons

- When an add-on is uninstalled, all installed DLLs are removed from Softimage and deleted from disk. If Softimage is currently using these DLLs at the time the add-on is uninstalled, Softimage may crash. For example, a render region showing the results of a packaged shader, a custom deformation operator, etc.

- When UI elements (toolbars, views, layouts) are removed (the file is deleted), the menu bar still presents them as available, selectable items, although they are actually uninstalled. Selecting these uninstalled items could have unpredictable results; however the application should not crash. Restarting Softimage removes the entries from the menu.

## Installing an Add-on of an Older Version

- Although the items contained in the addons of previous versions of Softimage are still supported, installing old layouts are not, because the file format and internal data structures have changed dramatically. When installing an add-on that contains an old layout item, a message is logged, specifying that the layout object has been skipped.