Abaqus Element set Not defined error

[siuu]

I am modelling an indentation experiment. Dymanic explicit with a time period of 0.3s
There are 3 parts: A triangular indenter, A spherical ball and a flat base.
I have applied rigid constraints along with a reference point for both the indenter and the base.
I have created a section for each part and gave the rigid bodies the same material as the ball ( as these 2 are rigid, they shouldnt be affected by the material) I have also not meshed these two parts, as they are rigid bodies.
I am looking to observe the reaction forces between the indenter and the ball, and any stresses and strain for the ball ( the ball has been meshed), and also track the displacement and velocity of the indenter (at the reference node)

However, I am getting these errors:
in keyword *RIGIDBODY, file "Job-1.inp", line 40306: Unknown assembly set INDENTER

in keyword *RIGIDBODY, file "Job-1.inp", line 40308: Unknown assembly set BASE

in keyword *BOUNDARY, file "Job-1.inp", line 40548: Unknown assembly node set SET-5

Element set assembly_indenter has not been defined

Element set assembly_base has not been defined

Element set assembly_indenter has not been defined

Element set assembly_base has not been defined

Element set assembly_indenter has not been defined

Element set assembly_base has not been defined

The element set assembly_indenter (used to define a rigid body) was not found.

Analysis Input File Processor exited with an error - Please see the Job-1.dat file for possible error messages if the file exists.

Would really love some help please and thank you

 

[FEA way]

I have also not meshed these two parts, as they are rigid bodies

Rigid bodies need meshes too unless they are analytical rigid but then only simple extruded/revolved shapes can be used.