Fundamentals > Relations and Parameters > Relations > Relations in Sections > About Creating Relations in Sections
  
About Creating Relations in Sections
A section relation captures relationships among section entities. The section relation is stored with the section and is evaluated by the system regardless of where the section is used.
You can use the following variables in the section relations:
Driven variables can be as follows:
Dimensions in the section (sd#) or in the parent model (d#)
In Assembly mode, dimensions in another model (d#:#)
User parameters in the parent model only (no session-ID suffix allowed)
Driving variables can be as follows:
Dimensions in the section (sd#, rsd#, or kd#), parent model (d#, rd#), or other model in an assembly (d#:#, rd#:#)
User parameters in the parent model only (no session-ID suffix allowed)
Tips for Creating Section Relations
Relations that define dimensions other than section dimensions are best defined at the feature or model level.
You cannot reference a parameter in another feature as a driving variable. For example, if dia is a dimension in another feature with fid_20, the system does not accept the following section relationship:
sd3 = dia:fid_20
However, you can establish the same relationship at the feature level or model level by using the model-level equivalent (d#) of the section dimension (sd#). Alternatively, you can create an intermediate user parameter in the parent model and then reference it from the section.
If you try to assign a relation outside of the section to a parameter that is already driven by another relation in the section, the system issues an error message upon regeneration. The same applies if you try to assign relations in a section to a parameter that is already being driven by a relation outside the section. Remove one of the relations and regenerate again.
When you create a relation of a graph feature, for example, sd1=evalgraph("CONIC......", trajpar....), this relation becomes a feature relation. Feature relations are evaluated after part relations and are solved when the feature to which they belong is regenerated. Therefore, if a relation performs geometry evaluation (for example, the distance between two points), it can give different results if used as a section relation as opposed to being used as a part relation.