====== Submodeling and Calculations ======

The ACS-SASSI User Interface Was intended to allow the user to create pieces of a larger model to do different types of analysis.  This is achieved using multiple commands documented in the command reference. However the procedure is always the same.


===== Cuts & Submodels =====

First the user must cut the model. A cut in this code is considered to be a subset of elements defined by the user. There are multiple commands to define what is going to go into the cut but the cut store the elements that within it by group and node number. These Commands such as [[ com:CUTADD ]] and [[ com:CUTVOL ]] can be reviewed in the [[ :Command Reference ]]. The user can review what elements are in a cut by using the [[ sassi:user_interface:Cut ]] Plot.

===== Calculations =====

The ACS-SASSI User Interface has the ability to aid the user with design calculations on models in memory. To use these commands as intended the user must first create a cut with the elements to be included in the calculation. Then the user should create a cross sectional model using the [[com::CSECT]] command. The cross-sectional model is a 3-d model base on where the plane defined in the CSECT command intersects with the elements in the Cut. The cut/cross-section plane intersection is then extruded out to a unit thickness to create the 3d model. A 3d model was used instead of the 2d for plotting purposes.

The cross-sectional model will have the same group/element numbers as the original model but the node numbers and locations will be changed to create the 3d unit thickness cross-section. The ACS-SASSI User Interface finds the intersection of a element with the plane and will adjust the extents of the element based on this intersection.  The ACS-SASSI User Interface calculates the intersection of a shells with the crossectional plane and shell thickness will be adjusted in the cross section when the Shell face is at an oblique angle to the cut plane. 

**Note:** The user my use the calculation commands on non Cross sectional models. However, the results of the calculations may not be useful for design purposes. For stress calculations the user should add stress data to the model before the Cross section is created.
  
===== Trans Commands =====

The Trans Commands act similarly to the cut commands but these commands directly transfer elements to the new model without the ability to review and change the data that is being transferred to the new model. For this reason it is suggested that the user use the cut commands instead for creation of a submodel. 
===== Example(s) =====
==== Cut Example ====
<code>
* Create a submodel of elements above ground surface and save it to a file
* Ground surface at 2.53
inp,model.pre
*<blank> can be lack of any characters or just white-space 
cutvol,3,<blank>,<blank>,<blank>,<blank>,2.53
cut2sub,3,1
actm,1
write,model above ground.pre,C:/users/user/.../
</code>
**Notes:** The <blank> in the [[com:CUTVOL]] command represent lack of arguments provided to the command. <blank> is used to help the user see the argument fields being skipped. The <blank> arguments will get default values when the command is executed in [[SASSI:acs-sassi user interface|ACS-SASSI User Interface]]

==== Calc Example ====

<code>
* Create a submodel of a wall and do calculations on it
inp,model.pre
readstr,stressfile.txt
cutvol,3,52.5,52.8,-320,320,2.53,45.22
* Create the crossection for calculation 
csect,1,3,55.6,0,4,1,0,0
actm,1
calcpar,1,0,0,0,1,0
calcm
</code>