Dynamic Blocks

Hello,

I thought about putting this in beginners thread but i am not an AutoCAD beginner, however, I never had to really use blocks. Can someone tell me why this very simple box is not fully constrained. I am use to Solidworks when it comes to constraining and I just have a feel for it with that program. Typically, just dimension everything from the origin. In AutoCAD I must be missing something. I attached my simple problem. Any feedback is greatly appreciated.BOX-TEST.dwg

You can add PARAMETRIC constraints (either dimensional, geometric or dynamic) to a block, or you can use the AUTOCONSTRAIN command, and specify what constraints you want infered, before you draw the block, and the software will try to apply your design intent. That option would probably be the most like Solidworks.

I don't use them, so can't tell you much about them, but on the MENU BAR, you can click on PARAMETRIC, or find it on the Ribbon as shown in the screenshot..

Since you are making a (dynamic) block you don't need any of those constraints.

I never had to really use blocks. Can someone tell me why this very simple box is not fully constrained.

I have renamed your thread since you're not talking about simple Blocks, you're talking about Dynamic Blocks.

Not sure what you mean by "fully constrained".

The only constraints I found were ones to keep the sides parallel and perpendicular to each other. I deleted all the constraints, and the block still functions by stretching in both directions with all sides still parallel, and perp to each other.

You don't need the redundant constraints. Dynamic block parameters have built in constraints. Linear is just that. The stretch will only take place in that one "Linear" direction. However, one can rotate the block in modelspace thereby changing the direction of "Linear". I have no clue how constraints applied to a block within the block editor would affect the block once inserted in modelspace.

Should the horizontal parametric constraint prevent it from being rotated, or from stretching once rotated? I just remembered to test it. They won't have any effect outside of the block editor at all. I just had constraint lesson #1.

See this screenshot this is what I am talking about when I say "constrained."

The ! sign says there are no actions to my parameter. I added a stretch action to parameter (distance 1)? Confused.

Did you remember to define the entities to which that action should be applied?

Block Works

I will mess around. Y not show what member that is unconstrained like every other design program. Very frustrating. Almost not a design program but a drafting one.

In the block editor, the "!" sign is to let you know that you have a dynamic parameter grip but that there is no action associated with it, when you only need and action to work in one direction only, it is normal to turn off one of the grips (in the properties palette - towards the bottom "number of grips") but you need to plan beforehand how you create the parameter, because turning off one grip, is as far as I know, dependant on the pick points when you created the parameter, ie when you only have one grip visible it is at the end of the parameter that was the last point picked, so you might need to delete certain parameters and recreate them. I've probably made this sound more complicated than it actually is, just bear in mind that grips can be removed and parameters should be created in the direction that you want them to work in the drawing.

Steven-g,

Thank You. Grip display at 1 instead of two fixes issue. AutoCAD prefers two have two separate parameters and actions in this situation to stretch both right and left. It sounds redundant but its the way its setup i guess. If i set a parameter distance on top of box and then an action and grip to 1 all is good. If I set another parameter on bottom and action and grip to 1 all is good. Just make sure to check correct start point. This is just a box. I guess you will get a feel for it.

If you want left and right it should be fine with just the single parameter, to be honest it does take some getting used to, as the logic isn't always logical, and if you want the same stretch performed left and right, you can just use one grip, but two actions working in opposite directions.