Precision in archicad

[Anonymous]

Hello everyone,

The tech at the office show me a wall and a floor junction went they zoom. Went they try to extend the wall the measure tool show zero. This not the first time this situation pop-up. Last time was, went we send a floor plan to the engineer to coordinate, they send back information that lines was at 0.0002 from the axe.

In archicad we were not able to see the difference.

Are we missing something

[Aaron Bourgoin]

ArchiCAD's default working units (and dimensioning units) are not set to a maximum. If you were modeling using the defaults, and verifying the accuracy of your work with dimensions, you may have introduced the error without being aware of it.

It's important for your team to check this as your work progresses. It's harder to find and correct.

Rather than an inaccuracy in the application, it is far more likely to be the result of human error.

[Anonymous]

The toughest to find problems are the smallest ones. 0.0002 (not sure what unit? degree?) is a really small deviation. Really hard to spot or even measure. Have you confirmed it in Archicad?

[Karl Ottenstein]

@mhoude,

Many of us have a set of 'working' dimension/unit preferences set to maximum to find badly modeled things... and then other sets for construction drawings (e.g., rounded to the smallest measurement that the contractor wants to deal with.)

But, whether you SEE the value or not ... it is important to model precisely. For example, when inserting a wall, never just read a value in the Tracker or coordinate box and click. ALWAYS type a precise value, OR snap to an existing element. Make sure that you are not snapping or modeling at an angle when you mean to be perpendicular or parallel. This is essential for proper modeling.

Even with all of the above, if you are modeling a large structure, and display dimensions at maximum precision, it is still possible in rare cases for a string of connected walls to seemingly not add up to exactly the sum of the parts... the final dimension could be off by 1/64" (or whatever the smallest metric unit representable internally is). That is neither a dimension or modeling error, but a numerical precision error of how decimal numbers are stored in a binary computer. Should have no impact on anything in practice. 😉