Variable Array of a Dynamic Block
Have a look at the attached block to see if it fits your needs.
Its an Arraypath inside a dynamic block. The length of the path a construction line with an Equal length constraint to another construction line with its length controlled by a Horizontal Constraint. The array divisions value is a User parameter that takes the horizontal constraint distance, divides it by 1000, rounds the result up and adds 1 to arrive at the correct number in the array without exceeding 1000 mm.
In an arraypath you can't dynamically change the item being arrayed. However, you can array multiple objects of different sizes and then choose which size is visible with a visibility state parameter. In the sample I posted there is a visibility state grip with 4 different sizes to choose from.
The visibility state selection could be done thru a linear parameter if that works better for you.
The array can be further adjusted with a couple of additional user parameters, one for the maximum distance between supports and another for a minimum distance before the second support appears. Right now the max is 1000 and there is no minimum.
I'm not able to do any screencasts during working hours, however I can do a few screen grabs if that helps and I'll take a guess at where you may be having a problem. There is a part of it that is sort of 'non-intuitive' where you need to type in the name of the user parameter as a value for the arraypath property. When you type in the name of the parameter into the array properties it will change to the current value of the user parameter rather than hold the name. Once its enter there seems to be no evidence as to where the value comes from. The red box in the image below comes from the user parameter "Spacing" in the dwg I attached in the prior post.
The value of the 'Spacing' user parameter comes from an expression, (ceil(d1/1000))+1 The expression uses the value of the d1 dimensional constraint parameter, divides it by 1000, rounds it to the next higher integer, and then adds 1 to arrive at the proper number of items to be in the array such that the distance between them never exceeds 1000 units.
Happy to help if I can
Thank you Mark, I have a set of steel stairs for a school, wham I'm trying to make is a dynamic block which allow me insert post @ around 5 feet between centers, then another block to let me insert pickets between those posts with no mere of 4" clear between pickets, pickets can be 1/2" or 3/4". square or diameter, please see attached photo,
Thank you very much in advance for your help, it takes too much time figuring spaces for each railing.
Does this need to be a dynamic block? (are you going to use it over and over again?)
You could do this with a polyline thru the railing for alignment, draw in the first post and spindle, the ARRAYPATH those objects as two different arrays. You can then specify number of object in the array, that it should use the entire length of the polyline, and then keep an eye on the spacing it creates such that it doesn't exceed you maximum spacing.
Sorry for the delay, my silly day job keeps getting in the way.
The attached file has 2 blocks with it. One for the railing post and another for the spindles
The one for the posts has an Arraypath of the posts along a construction line. The length of the construction line is controlled my a linear constraint. A user variable has a formula calculates how many posts should be in the array by dividing the value of the linear constraint by 60 (inches), rounding it down to one integer, then adding 1. The arraypath uses this user parameter as its value for the number of objects in the array.
The Spindle block works in a similar manner except that one needs to account the there not being a spindle at the beginning or the end of array. (as there is a post there) Two user parameters calculate the values needed for the array path.
I was hoping to get enough time to combine these into one dynamic block but it was going to take a little more time to solve the issue of intermediate spindles coinciding with posts in the middle sections of the railing. This could be handles with a simple wipeout included with the post array. Not elegant but would get it done. In the meantime you could insert the two blocks, select them both and pull the grip(s) both at the same time.
Sorry for the delay. I'm embarking on a job switch and my last day is tomorrow.
Access to creating User Parameters is within the block editor. On the ribbon there is a Parameters Manager. It will show you all the parameters within the block. From there you can create and edit the User Parameters.
