When a molecular project contains several render presets, it can be easy to lose track of which one you mean. A name may be familiar, or a preset may be selected, but those are different clues. SAMSON’s Node Specification Language (NSL) provides a compact way to describe render preset nodes using their names and inherited node attributes.
This guide focuses on the render preset attribute space, renderPreset, whose short name is rp. Its scope is useful to keep in mind: expressions in this space match only render preset nodes. That helps make a query more specific when your goal is to work with presets rather than nodes of other kinds.
Start with the preset’s name
The name attribute is inherited from the general node attribute space. In the render preset space, its short form is n, and the name is written as a quoted string. The documented examples are rp.n "A" and rp.n "L*".
When you know a preset’s label, a name-based expression gives you a direct way to refer to it. For example, rp.n "A" describes a render preset named “A.” The second example shows that "L*" is also a documented name expression. Treat these as literal examples from the reference; the page does not specify additional rules for interpreting the asterisk.
One practical habit is to preserve the quotes when writing a name expression. The attribute table specifies strings in quotes, which makes the intended value clear and avoids confusing the preset name with an NSL attribute or keyword.
Check selection without confusing the attributes
The attribute space also includes selected. It is inherited from node.selected, but it has no short name in this space. The reference gives two useful forms: rp.selected and not rp.selected. These let you express the selected and not-selected cases explicitly while keeping the query scoped to render presets.
There is also selectionFlag, shortened to sf, which is inherited from node.selectionFlag. The documented examples are rp.sf and rp.sf false. Both attributes are listed as accepting true or false, but they have separate names in the reference. If you are deciding which one belongs in an expression, use the attribute that matches the state you actually intend to describe rather than treating the two names as interchangeable.
A quick way to choose an expression
-
You know the preset’s name: start with
rp.nand put the name in quotes, as inrp.n "A". -
You want to describe whether a preset is selected: use
rp.selectedornot rp.selected. -
You specifically need the selection flag attribute: use
rp.sfor the explicit false examplerp.sf false.
These small distinctions make expressions easier to read later, especially when you return to a project and need to remember whether you were identifying a preset by name or describing its selection-related state. The short prefix rp also signals the attribute space at a glance, while the longer attribute names can make an expression’s intent clearer.
For the complete attribute reference and its inherited attributes, see the SAMSON render preset attributes documentation.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. Get SAMSON at samson-connect.net.