Component Schedule Expression Limitation (Need Help plz)

engr_shahid — Tue, 04 Aug 2026 06:52:16 GMT

Hi everyone,

I'm working on a BIM-based quantity take-off system in Archicad 29 and I've encountered a limitation that I can't seem to solve.

My Workflow

I created a Complex Profile Foundation containing multiple building materials/components:

PCC (Concrete)
Structural Brickwork
Damp Proof Course (DPC)
Waterproof Membrane

Using a Component Schedule, I can successfully extract each component separately by using the "Building Material / Composite / Profile / Fill" field. The schedule correctly displays each component with its own Net Component Volume.

For example:

Brick - Structural → Net Volume
Concrete - Structural → Net Volume
DPC → Net Volume
Waterproof Membrane → Net Volume

This part works perfectly.

The Problem

I created custom Property Expressions to calculate:

Number of Bricks
Cement
Sand
Aggregate
Cement Bags

The issue is that Property Expressions only expose the general "Net Volume" (Owner Element Volume) instead of the Component Net Volume.

Because of this:

Brick calculations are also applied to PCC, DPC, and Waterproof Membrane.
Concrete calculations use the total element volume instead of the current component volume.
I cannot calculate materials correctly for each individual component.

Another Limitation

Inside the Property Expression editor:

Component Volume is not available under Parameters & Properties.
Building Material is also not available, so I cannot write an IF condition such as:

IF Building Material = "Brick - Structural"

to limit the calculation to brick components only.

My Question

Is there any workaround to:

Access Component Net Volume inside a Property Expression?
Detect the current Component Building Material inside an Expression?
Calculate different values (Bricks, Cement, Sand, Aggregate, etc.) for each component within a single Component Schedule?

Or is this simply a limitation of the Archicad Expression Engine?

I'd really appreciate any suggestions, workarounds, GDL tricks, Python API solutions, or BIM workflow recommendations.

Thank you!

Operating system used: Windows

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Component Schedule Expression Limitation (Need Help plz)

My Workflow

The Problem

Another Limitation

My Question