The zero total mass is incompatible with the nonzero center of mass. Resolve this issue in order to simulate the model.

I am getting the above error message all the time. I have imported the CAD Assembly from the inventor. I have specified the material in the inventor itself. Please let me know where the problem is?

[Walter Roberson]

Does the material support density information? If so you might have configured it as 0.

Answer 1

[Steve Miller]

In your DataFile, there is a part set to have 0 mass but a nonzero center of mass. Likely, the density of the part is 0 in Inventor.

%Inertia Type - Custom
%Visual Properties - Simple
smiData.Solid(4).mass = 0;  % lbm
smiData.Solid(4).CoM = [1.9096113985112416e-316 2.7369230995704108e-310 0];  % in

You can either fix this in your CAD model, or you can modify the parameters directly in the ex_b_s_4_DataFile.m, setting the center of mass and inertia values to 0. Make sure this solid is rigidly attached to world or you will get additional errors related to infinite acceleration.

--Steve

[karim Jomaa zabadne]

@Steve Miller it doesn't work at all!!! can u post something that actually make sense?

[Walter Roberson]

If you look at lines 140 and 150 of the m file that the original poster attached, you will see that they defined two parts with mass exactly zero, but with CoM (centre of mass) not exactly zero (1e-310 range, which is about where the "denormalized numbers" start—numbers so small they cannot be represented as floating-point numbers).

When you have an object with mass 0, its centre of mass must be at exactly [0, 0, 0]. The CoM needs to be edited, or else you need to provide a non-zero mass.

[Steve Miller]

@karim Jomaa zabadne does the post make sense now? I highlighted the code that was incorrect, and Walter Roberson has given you very clear instructions on how you can correct it.