topic Re: Basic script example in 3ds Max Programming Forum

Basic script example

cprettyman — Thu, 17 Dec 2009 16:31:25 GMT

I'm very much a novice at scripting, in any language, so please forgive me if this is too basic a q.

I need to write what I suspect is an absurdly simple script. If I have a set of objects select (it's a large set, about 1500 objects), that all happen to be splines, I need to make them all renderable, spline (enable in renderer), regctangular, with a a specific set of dimensions (which we're still trying to determine).

I'm not asking anyone to write this for me, but it seems to me that performing the same properites change on a large number of objects is probably such a common scripting thing that someone probably has a sample sitting handy that they could offer as an example, and then I will work through it to make it do what I need (a good exeercise for my self education anyway)

thanks so much.

Re: Basic script example

Anonymous — Thu, 17 Dec 2009 17:57:23 GMT

Whenever you want to change the same thing over and over on a specific selection, you use a "for" loop. Like this:


for obj in selection do
  &#40;
  obj.pos =  -- Move all objects to 0,0,0
  obj.wirecolor = red -- Change the wireframe color to red
  --etc.
  &#41;

I think in your case creating the shapes in the script would be more efficient than modifying an existing set of shapes...if possible.

The MAXScript Help files have lots of example "How To" sections that should be enough to get you started. Good luck!

Re: Basic script example

Steve_Curley — Thu, 17 Dec 2009 18:08:51 GMT

Ok, if you want to write it yourself...

Things you'll need to know about.
For loops.
Collections.
The names of the object properties you want to change. Editable Spline objects are called "spline shapes" in Maxscript.

Iterate over the collection, each time around the loop set the rquired properties.

There is another way, but it's a little more cryptic (mapped functions).

Read up on all the above in the Maxscript help - if you get well and truly stuck, post back and I'll try and help you out.
Also, there are innumerable examples of this kind of procedure in this very forum - looking through some recent (and not so recent) threads should provide a fair overview, though not necessarily the specifics, of what you're trying to do.

Re: Basic script example

cprettyman — Thu, 17 Dec 2009 22:32:20 GMT

I think I got it. Im sure there are subtleties I could add - some sort of error checking, an if statement to make sure everything in the selection set is a spline. But, this seems to work.

for obj in selection do
(
obj.render_renderable = true
obj.render_rectangular = true
obj.render_length = 0.5
obj.render_width = 1.0
)

Re: Basic script example

Anonymous — Thu, 17 Dec 2009 22:37:16 GMT


for obj in selection do
&#40;
  if &#40;classof obj == Editable_Spline&#41; then
   &#40;
    obj.render_renderable = true
    obj.render_rectangular = true
    obj.render_length = 0.5
    obj.render_width = 1.0
   &#41;-- End If
   else
   &#40;
   print "Error. This object is not of the class \"Spline\""
   return undefined
   &#41;-- End Else
&#41;-- End For

I'm not at home, so you'll have to check if "Editable_Spline" is the correct class name.

Re: Basic script example

Steve_Curley — Thu, 17 Dec 2009 23:11:41 GMT

That's the basis of it, yes. You could put in a test as in Dave's post below, or you could create your own collection based on the current selection and the test. However, I think you need a double test, because classof a Line is "Line" (even if you "convert to Editable Spline") but any other shape like a rectangle (converted) is a "SplineShape".


mySplines = for obj in selection where &#40;classof obj == Line or classof obj == SplineShape&#41; collect obj

Then iterate over that with


for obj in mySplines do ...

But see Anubis's post below as well

Re: Basic script example

Anonymous — Thu, 17 Dec 2009 23:21:08 GMT

2 filtering tips using "where":

for obj in selection where isShapeObject obj do &#40;
 obj.render_renderable = true
&#41;

for obj in shapes where obj.isSelected do &#40;
 obj.render_renderable = true
&#41;

Re: Basic script example

Anonymous — Thu, 17 Dec 2009 23:26:15 GMT

That is indeed more concise. Is there a specialized way to add error checking for this example other than try/catch? Or are we assuming that a selection error should not be encountered with this filter?

Re: Basic script example

cprettyman — Fri, 18 Dec 2009 04:04:49 GMT

You guys are all awesome.

I might note that the context of this is a model that came from Revit (via FBX) to Max, and what I am doing is adddressing the muntins that divide up the windows. They were represented as lines in the revit model, and end up as splines in the Max model. I can select them all inteh select by name window becuse they all have "muntin" in the name. Conveniently, the Revit model was put together by a very careful, consistent team, so I can get away with less error checking.

That said, I appreciate the thoughts, because I can see myself reworking this script for later, less well built models where error checking is badly needed.

Thanks again.

Re: Basic script example

Anonymous — Fri, 18 Dec 2009 11:29:12 GMT

That is indeed more concise. Is there a specialized way to add error checking for this example other than try/catch? Or are we assuming that a selection error should not be encountered with this filter?

I always avoid Try/Catch 'cause its slow. And my code above will not need additional error checking. Well, then I work on selection I check it first and this is not to debbug but just to make the code faster. Im talking about this:


sel = selection as array
if sel.count > 0 do
&#40;
 -- the base of the speed up trick is that
 -- Max will not read the code here if selection is empty
&#41;

Re: Basic script example

Anonymous — Fri, 18 Dec 2009 12:53:14 GMT

And the obvious question offcourse, why don't you just select all spline objects and apply a renderable spline modifier?

;)

-Johan

Re: Basic script example

Anonymous — Fri, 18 Dec 2009 15:11:24 GMT

The same question came to my mind at the beginning but I assumed that Charles wish to enjoy learning MaxScript :)

Re: Basic script example

Anonymous — Fri, 18 Dec 2009 17:28:48 GMT

Anubis has made a great blog post on the subject of optimized selection checking and processing here: http://3dmyths.blogspot.com/2009/12/includeexclude-in-for-loops-via-where.html