When dealing with large molecular systems, visualizing and organizing your scene effectively becomes crucial. One of the frequent challenges faced by molecular modelers is locating and managing cameras, especially when working with complex molecular hierarchies or scenes with multiple viewing perspectives captured over time.
This post highlights how you can use the Node Specification Language (NSL) in SAMSON to efficiently filter and manage camera nodes using a set of documented attributes. Whether you’re setting up a series of animations or toggling different perspectives for analysis, mastering camera filters can simplify your workspace significantly.
Understanding the Camera Attribute Space
In NSL, camera nodes belong to a specific attribute space referred to as ca. This short name lets you quickly write expressions targeting only camera nodes. For example:
|
1 |
ca.n "A" |
selects a camera node with the name “A”.
Why Does This Matter?
Imagine preparing a paper or presentation involving several camera angles of a molecular interaction. Instead of sifting through all nodes visually or memorizing camera positions, you can instantly list your cameras using NSL filters.
Three Key Attributes to Remember
Here are three crucial attributes inherited by camera nodes:
name(short:n)
Allows filtering by name using wildcards. For example:
ca.n "View*"selected
Returns only selected cameras. For instance:
ca.selectedgets currently selected cameras, whilenot ca.selectedfinds those unselected.selectionFlag(short:sf)
Another way of testing whether a node is marked by the selection tool. For example:
ca.sf falsehelps exclude flagged nodes during filtering.
Use Case: When Simplicity Saves Time
Suppose your project uses five different cameras: “View1”, “View2”, “TopView”, etc. You’ve selected the best four to export an animation. Before rendering, you want to double-check their names and status.
With NSL, a simple query like this gives you peace of mind:
|
1 |
ca.selected and ca.n "View*" |
This filters to only camera nodes whose names start with “View” and are selected.
No Short Name for “Selected”? Here’s Why
Although the selected attribute is inherited from node.selected, it does not support the short name s. This avoids potential ambiguity when writing expressions. So if you’re wondering why ca.s returns nothing, it’s intentional design.
Conclusion
While simple in appearance, using attribute-based filtering for cameras can quickly clean up your workspace, speed up your workflow, and make complex molecular visualization tasks more manageable.
To learn more about other attributes and use cases, visit the official documentation page.
SAMSON and all SAMSON Extensions are free for non-commercial use. You can get SAMSON from the official website.