How can i avoid this: Dimensions of matrices being concatenated are not consistent

I understood this error message. But how can avoid it?

My Code:

r_inputdataSigmaX=[3 45 34;34 324 324];
r_inputdataSigmaY=[3 45 34;34 324 324;34 324 324];%is too big
r_inputdataTau=[,];

input_data_rainflow=horzcat(r_inputdataSigmaX,r_inputdataSigmaY,r_inputdataTau);

My idea:

1. To use another command to combine matrices vertical with different size?
2. To fill up the smaller matrice with zeros or NaN to get the same size? But how?

Thanks for your help.

[Philipp Mueller]

why is this question closed? sorry if i made a mistake