Not getting a good impression from SU Pro 2021

So, I decided to bite the bullet and see if the latest build of SU was better than the 2017. This was mainly because I thought that the animation using the Component Attributes was going to help me. So far I’m not that impressed. The idea seems very simple to use, but in practice, either it is move complicated than I understood or it is buggy.

Case in point. I have a set of gears that I want to have move. I was finding rotation of components was a bit tricky to manipulate, but I thought I finally got it. However, it would seem that there is a bug where by entering the same value to rotate will result in a different result.

Repo Steps:

  1. Load gear_set.skp (167.0 KB) .
  2. Open up the Component Attributes dialog.
  3. Click on the gear set component that is in frame.
  4. Change the value of gear set!angle to =1-1 (just setting value to 0). Note where the gear has moved.
  5. Now change the value of gear set!angle to =2-2 (just setting value to 0). Note that the gear has moved again.

The value has been changed from 0 to 0 to 0 and each time, the gear has moved to a new location. What’s up with that? I don’t see any reason why it should keep moving given the same value. I did try something similar before and it did work, but I no longer have the file. Any one have any idea what’s going on?

From my understanding (very limited) the custom input fields do not perform math in their native form. You may have to insert a function there to make it work. However, there’s something else going weird because the gear keeps moving in a weird path towards the inner gear. I don’t see any logic governing the location of the gears relative to the object box (preferred) or each other, and that might be your problem. Others with more experience might have an easy solution for you, but it would take me a while to figure out how to animate this. Also, if you want it to animate PROPERLY (that’s a big if) you’ll need to incorporate the pressure angle (IIRC) and ratios into the equations for the correct angular procession of each piece.

Wow. Really? That’s kinda strange.

The gears are to move around the ring gear. So, I’ve got it so that the first group layer of the gear will rotate around the centre of the ring gear and the 2nd group layer will rotate around it’s containing gear axis.

Hmmm, I’m not sure what you are getting at. How would that animate it properly? I was just taking the simplistic view that when the gear goes around the ring gear, that it would spin at the correct rotation ratio.

Thanks for your feedback.

I understand that’s what you’re going for, but I don’t see any logic in the variables of the dynamic components to provide that movement other than altering the “rotZ” value. Is there another variable hidden that I’m not seeing?

I think it depends on what you’re asking the field to do. When it’s being referenced by another field, things might get messy due to order of operations. I “think” you can use the VALUE(text) function to reference this operation safely. I tried it, and it worked (it gave the right value, but your model is still acting crazy). But I try to encase things like this in parentheses where possible or call on it with a function where not. Again, this doesn’t seem to be the problem.

So if the ratio is 4:1, the outer gear needs to rotate four times while it goes around the ring gear, meaning that every 10 degrees of procession around the ring gear causes 40 degrees of rotation in the outer gear. There should be an equation calculating the ratio to determine the placement of the outer gear and it’s rotation based upon an input (adding x degrees of rotation).

What really confuses me is how the outer gear moves with your animation. The location parameters aren’t set as variable on that component (from what I saw), so I don’t understand how they’re being manipulated by changing the gear set!angle.

Okay, I found the logic I was looking for. It was buried one layer deeper in the model. Wait, are you wanting this whole assembly to stay put and just spin? That would be much easier, and explain what I’m seeing. Gimmie a bit with this…

All your logic seems to be in place, but the Dynamic Components don’t want to play ball. I’m thinking two things: 1. This may be bugged. There’s no reason changing that angle value should relocate a subcomponent (or rescale it in some cases for me). 2. This may be too much for the dynamic component tree to handle. I’ve heard that the component trees get confused pretty easily in terms of referencing each other, and you’re actually asking a lot to happen here through one variable (efficient, don’t get me wrong; I like it).

I would try a couple of things to sort out what’s going wrong here. Build another model from scratch of simple boxes or whatever, and add the same logic components to them to see if it works. Same number of pieces and all that, but a simple fresh model with no frills. The other thing you might try is breaking down your OnClick command to a true/false state. Then allow that true/false state to trigger an animate command in the individual parts. That might keep the logic flow from “tripping on itself” going back and forth between levels of reference.

I’ve built simple custom codes like this in other CAD modeling software, and it’s always been pretty straightforward, but SketchUp is a little special in how it handles arguments, I guess. That’s why a lot of people build a custom extension in Ruby to handle things like this. That’s all the more I can guess at. Hope you find a solution!

For complex animations I would suggest using an extension.

Fredo’s Animator is one:
SketchUp Plugins | PluginStore | SketchUcation

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The ring gear stays put and the spur gears move. I only was working on the outer spur gear.

Yeah, that’s what I was thinking.

Thanks Dan. I’ll try that. Disappointing that SU Pro isn’t that Pro. This (and some others that I’ve not mentioned here) would definitely affect my decision on buying it. Still seems quite buggy and slow.

Well, with regard to this topic, Dynamic Components is an extension that runs it’s “onClick” animations the same whether on Make or Pro. It’s just that the DC authoring dialog is only available on the Pro edition.


You may not know this but Trimble has been developing a replacement for dynamic components, called Live Components. See discussion in it’s Labs category …

They’ve not yet implemented any authoring tools for LCs.

Here is another new extension that may interest you …

gear_set.skp (659.5 KB)