C_R

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2 years, 331 days

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These are replies submitted by C_R

@Joe Riel 

I overlooked the fact that my suggestion only makes sense for conventional compression springs.  It looks like we will have to live with the current implementation unless a better contact condition is proposed that can also handle an unstretched spring length s_rel0 of zero length or even of negative spring length. Some experts might find such length definition useful.

I am afraid that my main concern, of pointing out potential use errors of sign, is not well reflected in this post. Here is another attempt that hopefully better illustrates the consequences of an invalid configuration (red mass).

As indicated by the green mass, there should be no movement, but the red mass starts moving towards the contact point (at the x=0.1) because of an error of sign that is not obvious to avoid. It seems that the only way to deal with it is measuring s_rel and verifying the sign.

On a different case I was lucky enough to see that “something” was wrong with the results, but it took me considerable time to identify the cause. Unfortunately the text passage of the help page of the Elasto Gap component, that I consulted several times to make sure that I used the component correctly, is rather supporting the natural interpretation of a distance in terms of magnitude. I think a reminder of the importance of the sign would not harm (Or examples. The model gallery is full of it, but there is no way to filter for components used in a model.)

Thank you for your comment. I hope the discussion at least helps to draw attention to the fact that there can be errors of sign that are not obviously avoidable by either good practice or by component design.

Prismatic_Joint_wo_spring_with_Elasto_Gap.msim

@phil2  @Joe Riel 

The original proposal to add a visual marker to the components in the workspace is unlikely to provide a quick and complete overview for complex models.

I recently found that the initialization diagnostics app basically provides such an overview. Unfortunately, it doesn't always work, and sometimes it lists components that are set to ignore (see Q1 and Q2 in https://www.mapleprimes.com/questions/234537-Initialization-Diagnostics-Questions). Also, it is not possible to quickly check and change ICs in the model workspace (complex models can have many components with similar names, which makes finding components even more difficult).

For these reasons, I think a new item in the Model Tree for filtering components with ICs set would be the best place for a quick and complete overview.  A click on a list element would provide direct access to the ICs for checking and/or changing.

I have already submitted a software change request, but cannot provide more background to it. So I do it here.

@dharr 

I was not aware of this type of routing in the schematics. MapleSim uses the same type of routing for several physical domains, including electrical. Connections to a connection line are modeled with a dot. Such a connection is not mandatory. I (and probably other users) prefer to connect component to component. In such situations, ambigeous layouts are possible because MapleSim adds gaps to the routing where the lines are actually connected. Gaps are also added when connection lines cross.
It seems that this new way of layouting does not require gaps. How it works in multidomain layouts is hard to say without trying it.

Thanks for pointing out the new way of layouting.

@one man 

Perhaps the difference can be explained by the type of joints? Does your model correspond to the use of universal joints?

I used exclusively revolute joints.