Dynamic Block Moving Two Objects Proportionally

[jtylerbc]

I'm primarily an Inventor user, but not a stranger to AutoCAD.  I have made quite a few Dynamic Blocks, but most are relatively simple, and this is beyond my experience.

I've attached a file that includes a mockup block and an example of what I intend this to do.  I am trying to replicate the motion of a piece of equipment we are building.  The equipment was designed in Inventor, but will be used by project engineers in AutoCAD.  The attached block is a stripped-down mockup to figure out the dynamic functions, which I will then implement in the real block.

In the attached file, you'll see a green box and a yellow box.  The green box starts a certain distance off the baseline (5" in the example), and can move up within a range.  The function that I don't know how to achieve is that the yellow box should also move up, but at half the rate of the green one.  

A few things to keep in mind:

• The real block will use 3D solid geometry instead of the 2D used in the example, so any tricks with geometric constraints are probably not going to be viable.
• The equipment this represents is continuously variable (not incremental).  So a lookup table that gives the correct results at fixed positions isn't ideal.
• In the example block, the green box will end up outrunning the yellow one.  This is just a consequence of the arbitrary dimensions I used in the example - it won't do that with the real dimensions.

Any help would be appreciated.  This is something that would be pretty easy for me in Inventor, but I'm stumped as to how to achieve it with the AutoCAD Dynamic Block functions.  

[Libbya · Accepted solution]

Open your block in block editor.  Add another move action and associate it with the same Distance1 parameter making sure to associate it with the same point as the grip.  Add the yellow rectangle to the new move action's selection set.  Select the move action and go to the properties palette.  Fine the property called "distance multiplier".  The distance multiplier determines the motion of the action relative to each unit of motion of the associated parameter point.  Set the distance multiplier to 0.5.  Save close, etc...  

[jtylerbc]

Thank you.  I think that gets me what I need.  I have it working in the test block, just need to replicate the idea in the real one.

It seems I was trying to make it a lot more complicated than it is.  I was trying to find a way to link the values of two parameters together with an equation (ex. Distance2 = Distance1 / 2), and I couldn't figure out a way to do that.  While I'm still not sure if that's possible or not, apparently it is unnecessary in my application.  The "Distance Multiplier" property achieves the necessary result.  There are probably other places I could have used that in the past if I had known about it at the time.

[Libbya]

It is not possible to link two dynamic parameters with formulae.  You can usually accomplish the same result, though, by having an action associated with one parameter act on another parameter in the desired manner.  

[j.palmeL29YX]

If you are coming from Inventor you should be familiar with Constraints and Parametric Dimensions. 

These are simplified (2D only, not to use in 3d as also Dynamic Parameters and Actions) implemented in AutoCAD too (since ACAD 2010). 

An example how you can solve your problem (linking parameters) you find attached. 

If you have further questions, ask again. 

[jtylerbc]

@j.palmeL29YX, that's a good solution, but I think you missed part of my original post, or I didn't explain it clearly enough.

The block I posted was more of a conceptual example of what I'm trying to do, which both reduced the file size over the real block and kept any proprietary information out of it.  The real block uses 3D geometry - it is actually an Inventor assembly imported into AutoCAD, then simplified by stripping some unnecessary detail (fasteners, internal parts, etc.) out of it. 

So the Constraints and Parametric Dimensions make perfect sense in the example, but weren't a viable solution in the real block.

[j.palmeL29YX]

---

@jtylerbc wrote:

  The real block uses 3D geometry 

---

I know, I did read it. 🙂 

But if you think (or hope) you can solve your (3D) problem with dynamic parameters and actions (also only suitable for 2D), I wanted to draw your attention in the direction that you could also consider to try a solution by using constraints.