PlanSwift estimates paint by floor area and forgets primer plus the second coat. BuildBid reads the finish schedule and the wall sections together.
Painting takeoff (CSI Division 09 91 / 09 96) is a surface-area-and-coats problem. Interior wall SF = perimeter LF times ceiling height, minus door + window openings, by room and by finish code. Ceiling SF = floor SF, minus skylight + soffit cutouts. Each surface picks up the right finish code from the finish schedule, which maps to primer + topcoat + coat count and a specific manufacturer line. BuildBid reads the floor plan, the finish schedule, and the wall sections together so each surface is tied to its finish code and the gallons math is correct.
Trim is its own line item set - not rolled into wall SF. Base LF, casing LF (one side or two per door + window), crown LF, chair-rail LF, picture-rail LF. Each LF has its own paint-and-labor rate because trim takes 2-3x the labor per square foot equivalent (lots of brush work, cut-in, sanding between coats).
Coatings beyond standard latex have their own line items. Epoxy floors (CSI 09 67), intumescent fireproofing (07 81), elastomeric exterior, anti-graffiti coatings, traffic paint - each priced separately by SF with its own product, primer, and prep cost. The finish schedule call-outs flag these explicitly.
Prep work surfaces separately. Patch + sand existing surface (LF or SF), caulking at joints (LF), masking + protection (SF), staging or scaffolding for high walls (SF-day). New construction prep is lighter than repaint prep; the schedule notes specify the surface condition.