Sumaya,
Somehow the message you paste is still not the final one, and it appears to
have stopped before outputting the final metrics due to being stopped by
the debug console or something. But it matters not, usually these kinds of
problems are caused by initial penetrations anyway, as you would've seen if
the error message were output to screen. The rendering you show is
insufficient to show anything, as the spheres are not scaled by their real
size. Please render it with the Scale Array being the radius, and the Scale
Factor being 2. After that we may be able to see which part of the
configuration is problematic.
Whichever obj file you use, it has to make physical sense, a.k.a. no
initial penetration and has good mesh quality.
Thank you,
Ruochun
On Saturday, January 3, 2026 at 3:15:20 AM UTC+8 sumaya wrote:
> Hi Ruochun,
>
> Sorry for the previous email. Although the error stays the same. However,
> I was able to get the one vtk file that was generated. From the visuals, it
> looks like the wheel is slightly bigger than the soil. I am not sure if
> this is the reason that the unexpected velocity error is happening. Also, I
> have changed the wheel dimensions specific to my research. However, I have
> used already available viper wheel .obj file created by chrono. Do you
> suggest I replace that .obj file based on my research specifc wheel? Below
> is the screenshot and csv file attached.
>
> On Monday, December 29, 2025 at 3:22:29 PM UTC-5 sumaya wrote:
>
>> This is the final exit message.
>>
>> On Monday, December 29, 2025 at 2:12:07 PM UTC-5 sumaya wrote:
>>
>>> Hi Ruochun,
>>>
>>> Here is the error message(attached). Secondly, no vtk files were
>>> generated. I am running the script in debug mode in VS. The script crashed
>>> with the last message outputting frame=0(image attached). Thank you in
>>> advance.
>>>
>>> Sumaiya
>>>
>>>
>>> On Saturday, December 27, 2025 at 1:33:24 AM UTC-5 Ruochun Zhang wrote:
>>>
>>>> Sumaya,
>>>>
>>>> The test scene you are targeting appears to be perfectly doable, but in
>>>> order for us to help you, you need to present two things:
>>>>
>>>> 1. The error message you gave seems to be the corresponding part of the
>>>> code, rather than what got output to the screen... Please provide the
>>>> actual error message.
>>>>
>>>> 2. Please provide a visual rendering of the simulation scene, before
>>>> the crash. Even if it crashes right at the beginning of the simulation,
>>>> you
>>>> can still visualize the initial configuration. This is important and
>>>> without visuals, anything we can say is speculative.
>>>>
>>>> Thank you,
>>>> Ruochun
>>>>
>>>> On Saturday, December 27, 2025 at 4:33:57 AM UTC+8 sumaya wrote:
>>>>
>>>>> Hello,
>>>>>
>>>>> I am looking for some suggestions about how to fix my error for the
>>>>> script wheelDPsimplified. I have changed the script based on my research
>>>>> requirement. My terrain bed is made of glass beads of 3 mm radius, which
>>>>> is
>>>>> very small. The beads are a clump of two and purposely, I have overlapped
>>>>> them slightly. Now the volume is very small compare to the values
>>>>> provided
>>>>> in the demo script. My IXX, IYY, IZZ are also very small and I am not
>>>>> currently scaling them. There was issue with the bin size but I have
>>>>> temporarily fixed it with the following lines. However, I am currently
>>>>> getting unexpected velocity that's crashing the entire system. I have
>>>>> played with the terrain properties, step size and HPC sampler spacing but
>>>>> nothing seems to fix this problem. Can you please suggest what could be
>>>>> possibly happening?
>>>>>
>>>>> *The error message :*
>>>>> DEME_ERROR(
>>>>> "System max velocity is %.7g, exceeded max allowance
>>>>> (%.7g).\nIf this velocity is not abnormal and you "
>>>>> "want to increase this allowance, use SetErrorOutVelocity
>>>>> before initializing simulation.\nOtherwise, the "
>>>>> "simulation may have diverged and relaxing the physics may
>>>>> help, such as decreasing the step size and "
>>>>> "modifying material properties.\nIf this happens at the
>>>>> start of simulation, check if there are initial "
>>>>> "penetrations, a.k.a. elements initialized inside walls.",
>>>>>
>>>>> * Parameters Output : *
>>>>> Current number of clumps: 4216
>>>>> Number of total active devices: 1
>>>>> User-specified X-dimension range: [-0.45, 0.45]
>>>>> User-specified Y-dimension range: [-0.102, 0.102]
>>>>> User-specified Z-dimension range: [-0.155, 0.155]
>>>>> User-specified dimensions should NOT be larger than the following
>>>>> simulation world.
>>>>> The dimension of the simulation world: 1.9584000110626221,
>>>>> 0.24480000138282776, 0.48960000276565552
>>>>> Simulation world X range: [-0.54, 1.4184]
>>>>> Simulation world Y range: [-0.1224, 0.1224]
>>>>> Simulation world Z range: [-0.186, 0.3036]
>>>>> The length unit in this simulation is: 3.5623088680269976e-12
>>>>> The edge length of a voxel: 2.3345947397501732e-07
>>>>> The initial time step size: 5e-06
>>>>> The initial edge length of a bin: 0.012287999153137209
>>>>> The initial number of bins: 128000
>>>>> The total number of clumps: 4216
>>>>> The combined number of component spheres: 8432
>>>>> The total number of analytical objects: 2
>>>>> The total number of meshes: 1
>>>>> Grand total number of owners: 4219
>>>>> The number of material types: 2
>>>>> History-based Hertzian contact model is in use.
>>>>> The solver to set to adaptively change the contact margin size.
>>>>> The script crashes shortly after.
>>>>>
>>>>> *Terrain Properties and Co-ordinates : *
>>>>>
>>>>> x y z r
>>>>> 0.0015 0.0012 0 0.003
>>>>> 0.0045 0.0028 0 0.003
>>>>>
>>>>>
>>>>> Glass beads : auto mat_type_terrain = DEMSim.LoadMaterial({{"E",
>>>>> 6.5e10}, {"nu", 0.245}, {"CoR", 0.926}, {"mu", 0.16}, {"Crr", 0.01}});
>>>>>
>>>>> // Define the terrain particle templates
>>>>> // Calculate its mass and MOI
>>>>> float terrain_density = 2500;
>>>>> float volume1 = 1.99e-07 ;
>>>>> float mass1 = terrain_density * volume1;
>>>>> float3 MOI1 = make_float3(1.431e-12, 9.058e-13, 1.282e-12) *
>>>>> terrain_density;
>>>>>
>>>>> HCPSampler sampler(0.025f);
>>>>> float sample_halfheight = 0.124;
>>>>> float sample_halfwidth_x = 0.42;
>>>>> float sample_halfwidth_y = 0.098;
>>>>> float offset_z = bottom + sample_halfheight + 0.01f;
>>>>>
>>>>
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