In a busy molecular scene, it is easy to lose track of the view controls among structures and other nodes. If you need to identify camera nodes with SAMSON’s Node Specification Language (NSL), the camera attribute space gives you a focused way to describe them—without confusing camera-specific queries with queries for other kinds of nodes.
Start with the camera namespace
Camera attributes belong to the camera attribute space, whose short name is ca. This space matches only camera nodes. That scope is useful when you want an expression to be about cameras rather than every node in the document.
For example, the full attribute name and short name can both express a name query:
ca.name "A"ca.n "A"
The short form is handy when you write expressions repeatedly; the full form can be easier to read when you return to an expression later. The reference also lists ca.n "L*" as an example. Use the documented example as a starting point when matching camera names, and check the broader NSL guidance for details about expression syntax.
Check selection state explicitly
Two related attributes are easy to mix up: selected and selectionFlag. The camera reference lists both as inherited from the general node attribute space, but their expressions are not written identically.
To query whether a camera is selected, use:
ca.selectednot ca.selected
For cameras, selected does not have the short name s. In other words, use the full form shown above rather than assuming that a short name available elsewhere is valid in the camera attribute space.
selectionFlag does have the short name sf. The reference gives these examples:
ca.selectionFlagca.sfca.sf false
Both attributes accept true or false. If an expression is not behaving as expected, checking which attribute you meant—and whether you used its supported name or short name—is a simple first troubleshooting step.
A practical way to build a query
When you are trying to isolate a camera, begin with the camera scope, then add one attribute at a time. For instance, start with a name expression such as ca.n "A". If you need to distinguish cameras by selection state, test ca.selected or not ca.selected separately. If your question is specifically about the selection flag, try ca.sf or ca.sf false.
Keeping these checks separate makes the expression easier to understand and helps pinpoint a typo. It also prevents a common assumption: that every attribute inherited from nodes has the same shorthand in every specialized attribute space. Here, name uses n, selectionFlag uses sf, and selected has no short name for cameras.
This reference describes which camera attributes and values are available; it does not, by itself, explain every aspect of NSL syntax or what an application action will do with a query. For broader syntax and examples, consult the NSL overview and its examples. For the complete camera attribute reference, see the camera documentation.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. Get SAMSON.