MaplePrimes - MapleSim Posts and Questions

The intermediate axis theorem with H2O and MapleSim

C_R — Sat, 14 Mar 2026 22:21:11 Z

I was wondering whether a water molecule exhibits the intermediate axis theorem (IAT) effect.

I was also curious if a tool like MapleSim could be used for simulations, as it is designed with technical applications in mind. (It would have been handy to enter parameters in Angstroms and atomic mass, but MapleSim only provides length in mm and mass in grams for small objects.)

The atoms of the H2O molecule form an obtuse triangle. An obtuse triangle exhibits the effect when rotated about its intermediate axis (horizontal axis in the image below) provided it consists of equal point masses (more details here) which is not the case for oxygen and hydrogen.

Building and running a model is quick since geometry and masses are available online. Two molecules are modeled in the attached file with parameters from different sources. The left model in the image below represents the atoms as three discrete point masses without individual rotational inertia. The system's total inertia is derived entirely from the spatial distribution of these masses. On the right, the entire molecule is modeled as a single lumped mass located at the center of mass (CoM), with the molecule’s full rotational inertia tensor applied at that point.

IAT_H2O.msim

Both models are rotating about the assumed intermediate axis at 3 THz (3 trillion rotations per second), which is about two orders of magnitude less than near-infrared light (just beyond the visible spectrum). To generate the IAT effect an orthogonal tiny initial “kick” of 0.001 Hz was added.

Visualizing was not so easy since the models are in the picometer range. It was difficult to locate the molecules by zooming with the mouse wheel (the button “Fit scene” on the 3-D Playback window did not work). Running an animation to visualize the IAT effect was not possible because the display speed could “only” be slowed down by a factor of 2^31 (see A in the image below). However, the slider C to move back and forth in time worked. The time (B) was always rounded to zero due to the very short simulation time span of 1E-10 seconds (i.e. 10 picoseconds).

Export of an animation movie worked better. Over the displayed timespan of 10 ps the molecules flip 2 times back and forth. This corresponds to a flip frequency of 200 GHz.

Time is still not displayed in the movie but that is pretty much all what did not work. Overall, a good performance. Also the numerical results did not show signs of loss of fidelity despite the atomic scale of the objects and the very short time span.

In reality, the rotation of a dipole results in the emission of electromagnetic radiation, which dissipates energy and decelerates the molecule. How can this damping effect be modeled in MapleSim? Someone has an idea?

Does MapleSim support the Modelica language model?

wswain — Wed, 25 Feb 2026 18:52:42 Z

I have tried to create a function "modelica style" that acts as a custom component.

The Modelica code editor recognizes it. It correctly sees the language constructs "function, parameter, etc." and then the block has the {} symbology showing it is a function. Also, the Syntax Template doesn't seem to work per chapter 07. i.e., the reference of "function" plus CTL-SHIFT-SPACE does nothing.

However, trying to call this does not work and errors that the function is being called from main as a public declaration and gving the named function "myfunction_1" instantiation within main which errors out.

Modelica coide in Main: public MyFunction myfunction_1 annotation(Placement(transformation(origin={120.0,160.0},extent={{-20.0,-20.0},{20.0,20.0}},rotation=0)));

MyFunction is declared below Main along with another custom component model class "UseMyFunction" that calls this function with the variables being used in the simulation.

Where can I find the modelica language references that MapleSim accepts in the modelica coding region?

This mini-attempt is to find the usage syntax and method to reach higher custom functions that act similar to "Math" code blocks in the library.

Bill

Why simulations can go nuts

C_R — Sun, 16 Nov 2025 13:29:05 Z

The Schatz Mechanism should move like this

However, with the default solver settings it froze after a few seconds in a planar link configuration. To make it run, I played around with advanced solver settings. Here is one attempt that went nuts:

(More solver settings for strange behavior can be found here: Schatz_Linkage.msim)

Some people might find this amusing. Of course, it is less fun when the initial plan was to spend an hour just for fun with a simple model (an hour is a fair estimate for similar simple looking models in MapleSim). The immediate reaction when seeing such simulation results is to blame the software for being either buggy or incapable. In this case, however, this was not the case, but identifying the root cause was not obvious.

The Schatz mechanism is a so called closed-loop mechanism where the links of the mechanism form a loop (the ground in the model closes the loop). In general, building and modeling mechanisms with loops is less straight forward than thought. Without a-priory knowledge or help (either by documentation or software hints) users can quickly find themselves in a situation of desperate trial and error. What was easy with other models can become a frustrating experience with unsatisfactory outcome. This happened to me on various occasions.

What makes closed-loop mechanisms more challenging? After resting for a long time on my virtual pile of unanswered questions, it turned out that the model, on top of being a closed-loop mechanism, is ill-conditioned: The Schatzmechanism is an over-constrained mechanism that is only mobile for certain geometric parameters. MapleSim can simulate such over-constrained mechanisms, but this can be a balancing act for the solver.

Who could have known this? A knowledgeable expert might say that users who do not know what they are doing should not use the software. But how to become aware of over-constrained assemblies when building and running a model in MapleSim does not require to be an expert? In this case the geometry was taken from a reference that sets the length of the ground link to Ö3. Model build, assembly and simulation instantly worked … but not for an extended time span.

In retrospect, everything is clear. Models that do not assemble do not fit together. Models that freeze in motion “jam numerically”. Linkages and joints of closed-loop mechanisms made of infinite stiff components may not fit together in all geometrical configurations. During runtime, after successful assembly, a stiff model can make a simulation sensitive to numerical errors. This does not mean that the user is dealing with a so-called numerical stiff problem that can be addressed by using stiff solvers. In this case, stiff solvers could not prevent sudden freeze or inversion of movements.

The only remedies that work for infinite stiff and over-constrained mechanisms are the ones that work also in real life. By either introducing mechanical play or elasticity in supports, joints and links, the simulation becomes robust. Numerically, for this case where none of the many advanced solver options made a difference, a simple increase of the relative error in the standard simulation settings worked. This remedy could be described as introducing more numerical play. Interestingly in a completely different approach of animating a Schatzmechanism @one man also needed to introduce “deformations” in his simulation to make it work.

The Schatzmechanism is of little commercial interest and can therefore be shared. Is it a rare case of successful assembly and freeze during runtime or is it more frequent that users run into similar problems? Only MapleSoft can tell, but in the latter case it could make sense that MapleSim supports the user. I see several possibilities for that:

A more prominent mention in the documentation that kinematic loops require caution could raise awareness.
Algorithmically detecting kinematic loops and informing the user that closed loops can be potentially over-constrained in certain geometric configurations.
(If possible, analyzing the Jacobian in the frozen configuration might give better hints than solver messages during runtime can provide. The attached model gives the hint with MapleSim 2025.1 that the error tolerance might be too tight, but no indication why.)
Implementing the mobility formula, analyzing closed loops and issuing a warning when the mobility M is less than 1 (meaning no degree of freedom)

The latter option sounds appealing. However, the degree of freedom calculated by the mobility formula only provides a necessary but unfortunately not a sufficient condition for mobility. For example, connecting a prismatic joint coaxially to another increases the mobility by one but does not add to the mobility of a mechanism. This means that an advanced algorithm must take the orientation of joints into account to determine the effective degrees of freedom. On the other hand, the Schatzmechanism and some other mechanisms have a mobility of M=0 but can be mobile for certain geometries.

Should Maplesoft implement mobility analysis or are CAD tools that offer some sort of mobility analysis more suitable? In my opinion, from a conceptual point of view, it would be beneficial and faster to have this support already in MapleSim before going into details.

Should the user refrain from modeling infinite stiff mechanisms? I do not think so because they are useful in the context of deriving (analytical) forward and inverse kinematics. Furthermore, there are more mechanisms out there that are mathematically, according to the mobility formula, immobile but useful in daily life. The telescopic fork is a prominet example.

Final note for math enthusiasts:

The Schatzmechanism (invented by Paul Schatz) is a byproduct of the inversion of a cube. Recalling that the diagonal of the unit cube is Ö3 gives a hint of why the Schatz mechanism becomes mobile for this parameter. Also related to the inversion of a cube is the oloid: a solid with a developable surface that touches with its entire surface a flat surface when rolling. The oloid and the Schatz mechanism are closely related, which can be appreciated from this video.

MapleSim for Web Converting Systems - Industry News for Fall 2025

alex_b — Thu, 13 Nov 2025 18:08:16 Z

Maplesoft continues to bring technology, collaboration, and learning together. Here’s some of the exciting industry news from the world of web converting and high-precision manufacturing lines, and what’s new with MapleSim for Web Converting Systems software.

How is MapleSim helping web converters and manufacturers?

From EV batteries to flexible packaging and medical films, industries that rely on thin web materials are advancing at remarkable speed. To keep pace, engineers need tools that let them model, simulate, and optimize every detail of their process with accuracy and confidence. Processes that once relied on intuition and trial-and-error are now guided by advanced modeling and simulation, such as MapleSim.

Using MapleSim simulation, engineering teams can perform process validation testing virtually - saving time and money compared to physical testing. The virtual models are used to explore and accelerate production — and the new release of MapleSim delivers a powerful set of features to make that possible.

What’s new in the latest MapleSim release?

The new release (available today) enhances MapleSim’s ability to answer “what-if” questions about industrial systems, easily review and compare results, and find strategies to improve production.

For converters and web material manufacturers, it is now even easier to create models of roll-to-roll systems. The updates to MapleSim for web converting systems include pre-built components for modeling spans and applying control during rewinding and matching tension profiles with PLC settings. There is also a new Utilities section to help users to handle sensor data and perform common calculation tasks.

These all reduce the effort to build and update models and add more detail to the simulations. The result: faster to innovate, shorter testing cycles, and more value from every simulation.

You can read more about the MapleSim new features.

Announcing the new Research Partnership Program for MapleSim

We are pleased to announce a new collaboration between Maplesoft and the research teams that are actively advancing converting and web manufacturing processes.
The MapleSim for Web Converting Systems - Research Partnership Program:

To support research communities across the web handling industry by providing licenses for MapleSim for Web Converting Systems at NO COST.

Our goal is to equip researchers with the same advanced modeling and simulation tools used in industry, helping them explore new concepts, test ideas, and drive meaningful discoveries.

Focus areas for research include:

manufacturing foils, plastic films, non-wovens, and other thin web materials.
any specialty process for handling or producing medical equipment, semi-conductors, or EV batteries.

More details of the program and the application process are available on this page.

How Simulation Gives You Operational Insights

We have a new web series of articles “R2R Operational Insights” that showcase the ways MapleSim models deliver deeper insights, greater efficiency, and better product quality. These modeling use case articles are sprinkled with customer stories from the world of packaging, EV battery manufacturing, and printing.

You can browse the R2R Operational Insight articles here.

Conclusion: Try MapleSim for Yourself

Together, these updates make it easier than ever to simulate, innovate, and learn in web-based manufacturing and design.
-->Start your Free Trial!

Maple and MapleSim 2025.2 updates

TechnicalSupport — Thu, 13 Nov 2025 17:11:08 Z

We have just released updates to Maple and MapleSim.

Maple 2025.2 improvements include fixes to print layout, PDF export, tooltips for keyboard shortcuts, Plot Builder, and more. We recommend that all Maple 2025 users install this update. This update is available through Tools>Check for Updates in Maple, and is also available from the Maple 2025.2 download page, where you can find more details.

At the same time, we have also released an update to MapleSim, which includes enhanced tools for comparing models and analyzing simulation data, and improved runtime performance for MapleSim connectors.You can find more information on the MapleSim 2025.2 download page.

FFT in MapleSim

C_R — Wed, 02 Jul 2025 08:01:29 Z

I came across this

Can these library components be used to perform FFT on signals in MapleSim?

Any guidance on FFT and MapleSim appart from exporting to Maple would be very much appreciated.

(Easy) frequency analysis is among the top features I am missing in MapleSim.