2.1.1180 Part 4 Section 4.6.12, bldDgm (Build Diagram)
a. The standard implies that the bldDgm element specifies how to build animation for any diagram.
PowerPoint only uses this element for OLE diagrams.
b. The standard places no restrictions on what the spid attribute refers to.
PowerPoint requires that the spid attribute reference a valid OLE diagram that is present on the slide.
c. The standard places no restrictions on the relationship between the spid attribute, the grpId attribute, and the parent bldLst element.
PowerPoint requires that the combination of the spid attribute and the grpId attribute on a given bldDgm element form a unique pair within the parent bldLst element.
d. The standard places no restrictions on what the grpId attribute refers to.
PowerPoint requires that the grpId attribute reference a group that is present in the timing tree.