This is an old revision of the document!
Table of Contents
Unit System
Intact.Simulation computations are fundamentally based on the unit system in use in the Rhino document. Failure to pay heed to the unit system can lead to unexpected and incorrect results.
For example, consider a beam restrained at the left end with a 1000 N load applied to the right end as shown here. With a simulation set up using millimeter length units in Rhino, the danger level in the beam exceeds 1 almost everywhere and indicates the beam is grossly overloaded.
However, if the beam is modeled with units of meters, the result is quite different: the beam will not fail. Note that in both cases, Rhino shows the dimension of the beam to be 10.00.
Unit Systems in Intact.Simulation
There are two areas which users must be cognizant of units when using Intact Simulation for Grasshopper.
The default unit system of the project
The default unit system is based on the length units of the current Rhino document and is applied to the geometry and results that are being displayed. The unit system is as follows:
Units for Input Quantities
- Note that the simulation input quantities are in MKS for the beta. We will soon provide the ability to specify units when entering physical quantities like Pressure.
Derived Units
Derived units such as acceleration, torque, and density are consistent within each unit system.
- Linear acceleration units are length/s2
- Torque units are force·length
- Density units are mass/length3
Independent Units
Across the several unit systems, rotational units are the same. Namely:
- Rotational velocity units are rad/s
- Rotational acceleration units are rad/s2