## Robot Structural Analysis

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# Tables - Sum of values

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What does "sum of val", "check val" precision mean? What does it show?

Does Sum val(ue) give me the sum of forces responsable for the reactions?

Solved! Go to Solution.

# Re: Tables - Sum of values

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Check this help topic:

http://docs.autodesk.com/RSA/2012/ENU/filesROBOT/G

**Rafal Gaweda**

# Re: Tables - Sum of values

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Thanks! Sum of value is still not very clear to me though.

"Sum of val. - An arithmetic sum of values of forces and moments for a given direction for the currently-filtered nodes."

Sum of what values and which direction?

# Re: Tables - Sum of values

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Take a look below:

- selection in green

- direction = columns (yellow, blue)

**Rafal Gaweda**

# Re: Tables - Sum of values

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Thanks. It is simply the total of the reactions of the selected nodes then?

In my case I selected all the nodes, but the the sum of value for the moments are not equal to the sum of forces.

In fact I changed all my supports to pinned so I didnt have any moments in them, but the sum of reaction for those nodes still remain? I dont get how that adds up.

# Re: Tables - Sum of values

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So either you have elastic supports \ ground on model or you are looking on nonconverged results of nonlinear case.

Example below

**Rafal Gaweda**

# Re: Tables - Sum of values

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from the RSA Help it is stated that :

"In quadratic combinations for cases of the seismic or spectral analysis, the sum of reactions and the sum of forces are calculated by adding the values of the respective sum of values and the sum of forces for individual vibration modes"

Can we have a little more explanation ie : the somme of reactions are equal to ....

and the somme of forces are to....

in this case (quadratic combination) the "somme of values" have no signification ( it still just a arithmetic somme below)

Thank you

# Re: Tables - Sum of values

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It is answered in the mesage 2 of this post:

http://forums.autodesk.com/t5/Autodesk-Robot-Struc

Regards,

**Pawel Pulak**