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--- wiki:sns:intactgh:consistent_units [2023/05/16 10:34] – [The default unit system of the project] goldy
+++ wiki:sns:intactgh:consistent_units [2023/06/07 11:03] (current) – paul
@@ Line 3: / Line 3: @@
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 ====== 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.
+The geometry simulated by Intact.Simulation is based on the unit system used in the Rhino document, which can be set in the Rhino file settings. Other input quantities, such as vector loads or pressure loads are based on the Meter Kilogram Second (MKS) unit system by default. The unit system can be changed by right-clicking a block and selecting a different unit system.
 <WRAP group>
 <WRAP half column>
-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.
+Failure to pay heed to the unit system can lead to unexpected and incorrect results.
+Choose a different unit system by right-clicking on the block and selecting the unit system.
 </WRAP>
 <WRAP half column>
-{{ :units_box_mm_results.png?400 }}
+{{ :wiki:sns:intactgh:units_context_menu.png?400 }}
-</WRAP>
-</WRAP>
-<WRAP group>
-<WRAP half column>
-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.
-</WRAP>
-<WRAP half column>
-{{ :units_box_meters_results.png?400 }}
 </WRAP>
 </WRAP>
 ===== 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 is Meter Kilogram Second (MKS). The supported unit systems are described in the following table:
-====  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:
-{{:wiki:sns:intactgh:pasted:20220809-214029.png?700}}
-====  ====
+^ Analysis units   ^ Mass                  ^ Force  ^ Stress               ^ Length ^
-  - (Note that the simulation input quantities are in MKS for beta. We will soon provide ability to specify unit when entering physical quantities like Pressure.
+| MKS (m kg s)     | kg                    | N      | Pa                   | m      |
+| CGS (cm g s)     | g                     | dyne   | dyne/cm<sup>2</sup>  | cm     |
+| MMS (mm Mg s)    | Mg                    | N      | MPa                  | mm     |
+| FPS (ft lbf s)   | slug                  | lbf    | lbf/ft<sup>2</sup>   | ft     |
+| IPS (in lbf s)   | lbf s<sup>2</sup>/in  | lbf    | psi                  | in     |
 ===== Derived Units =====