Seismosoft | Earthquake Engineering Solutions

For a 2D simple model, I ran three analysis. The only different between tge analysis was the diffrent in defining mass and loads to the software in "gravity and mass" tab in setting. The results of these three models should be the same, but they are realy different.
The masses were difined in additional mass elements. The loads were also calculated by "additional mass element" * 9.81.
I applied these calculated loads as distributed loads elements. The special weights for concrete and steel was considered a zero value.
Why there is diferent between the results of these three similar models?

I suggest a careful analysis of the various settings for the 3 models. It is not clear to me the various differences. You will learn a lot by going through the debugging process. If your efforts prove futile, Violet, feel free to send me the models and I will look them over.