Thank you for your dedicated efforts in developing the framework. As a graduate student, I am currently utilizing SimPEG for my research, specifically focusing on studying 3D TDEM modeling code.

In my current work, I am conducting forward modeling using a 100 half-space model. To achieve this, I have implemented the “Trapezoidal waveform” with an on-time interval of 1.945 msec, and I have employed an OcTree mesh. Both the source and receiver locations have been positioned above 45 m from the surface. For a visual representation, please refer to the provided image.

Unfortunately, despite following the described modeling steps, I have encountered an issue where the predicted values are so instable.

### SolvewWarning ### : Accuracy on solve is above tolerance: 5.8e-6 > 1e-6

Additionally, I am using the following line of code for simulation:

simulation = tdem.simulation.Simulation3DMagneticFluxDensity(

mesh, survey=survey, sigmaMap=model_map, Solver=Solver, t0 = 0)

To obtain the turn-off stage voltage response, I set value of t0 to 0. However this resulted in all the predicted values turning into zeros.

I would greatly appreciate any guidance or suggestions you can provide to help me overcome this problem.