calculation - part 1

Sfere2 is build to allow calculation to run parallel to the interface. This means that while the structure is still being build, results of a mechanical analysis can be shown already. This can be quite useful for direct feedback on the functioning of the structure, and if any mistakes are made, they'll give themselves away almost immediately.

Being as this is a Beta-version and that the calculation-methods are the most experimental part of the program, the calculation-interface is the most complex interface of the program.
You are advised to carefully read both parts of this chapter before attempting to start calculating.

starting calculation
Enabling and disabling the background calculation is done using Calculate.

  Calculate     Calculate > Calculate  
Enable or Disable background calculation.
[default accelerator: keyboard F9]


As soon as calculation is enabled, the visual feedback starts.

visual calculation feedback
By default "Display Displaced Members" (  View > Display > Displaced Members  ) is enabled. This will show the displaced members within the view.

KNOWN BUG: The orientation of the cross-section of a member does not follow the rotation of the structure. This is because the currently available calculation engines do not take member rotation in account.
WORKAROUND: None. But using the orientationless Tube-shape doesn't show this 'feature'.

INSERTED BETA-RELEASE 2 NOTE:
DISPLACED MEMBERS CAN NOW BE DISPLAYED USING THE NORMAL STRESS AS COLOR.

Select different methods using View > Display > Displaced Members.
Setup colors and stress exaggeration in the 'Stress Display Settings'-page of the View-tab on the Main Console.
Extended explanation of these features will incorporated in future versions of Sfere2.

x-ray settings
Depending on the X-Ray settings of the view (  View > Settings > X-Ray > ...  ) the members and displaced members are drawn transparent.

X-rayMembersDisplaced Members
AllTransparentTransparent
NoneSolidSolid
ModelTransparentSolid
DisplacementsSolidTransparent
Automatic (default)
if calculating: 
else: 
Transparent
Solid
if calculating: 
else: 
Solid
Transparent


an example with x-ray set to automatic

before calculation:
no displacements are displayed because there are no calculation results available.
during calculation:
displacements are drawn solid and the original structure is drawn transparent.
after calculation:
now displacements are drawn transparent, this indicates that any modification to the original structure is not taken in account for the displaced members.



the fun of background calculation and it's drawback
The obvious bonus of doing background calculation is the fact that optimization of the structure becomes far more intuitive. Changing properties have an immediate effect. For example:
a truss
moving the top-center member down decreases the overall moment of inertia of the structure:
deformation in the center increases.
moving the top-center member up increases the overall moment of inertia of the structure:
deformation in the center decreases.
removing the top-center member all together increases the deformations. the only thing keeping the structure up is the tension in the lower members
disabling support of the front-left joint does not improve matters.

All these actions were done without stopping the calculation.
However, there are cases where this doesn't apply: when the structure collapses

example of a collapsing structure
the structure starting calculation reducing elasticity too much leads to collapse fixing elasticity does not 'un-collapse' the structure

reset calculation
If the structure collapses and efforts are being made to avoid collapse, it is sometimes necessary to reset the calculation. This is done using Reset Calculation.

  Reset Calculation     Calculate > Reset  
Reset the calculation.
[default accelerator: keyboard Backspace]


Resetting the calculation sets all deformations to zero.
When calculation is (re-)started a reset is implied.