Component Schedule Expression Limitation (Need Help plz)

[engr_shahid]

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.

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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.

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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.

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My Question

Is there any workaround to:

1. Access Component Net Volume inside a Property Expression?
2. Detect the current Component Building Material inside an Expression?
3. 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