A little update. The behavior I describe below seems to be an undocumented limitation of dynamic components. My work around is to place all the attributes at the top layer (cascading them down step by step as needed) and only set the component options at the top level. When sub-components "fly-apart" a component refresh normally does the job and does not lose the attributes.

I am still wondering if anyone else has noticed this limitation?

Hi Eric,

I am no expert but my understanding is that the web site contains javascript and dhtml that communicates with the ruby plugin using calls described here:

http://code.google.com/apis/sketchup/docs/ourdoc/webdialog.html

Doing this requires expertise in Ruby, Javascript and dhtml.

Hope this helps.

I am hoping someone can explain the behaviour of the attached dynamic component.

This simple example starts with a set of nested cubes. Note that the location and size (x,x,y,LENX,LENY,LENZ) of the cubes have been constrained with "=".

One of the subcomponent cubes (a component instance) is selected and a material attribute is changed to Blue.

A second subcomponent is selected and changed to material Red.

A third subcomponent is selected and changed to material Yellow. Note how the cube moves to a location near the origin. This location happens to be the absolute x,y,x coordinates of the cube. The cube appears to have forgotten the location of the parent component.

Selecting and refreshing the set of 4 cubes sets the material color back to the green default as expected but does not correctly reposition the set.

Refreshing the entire dynamic component (Cube Group) clears everything and resets the position.

Note that it is possible to change the particular cube but not more than a couple before the same issue repeats. This behaviour is occuring with other models built completely differently.

Does anyone understand what is going on? Your help is much appreciated.

Odd Dynamic Component Behaviour.skp

Thanks guys. My math is so rusty that I did not realize that a 4x4 transformation matrix had a "standard" mathematical definition.

Thank you!

Pity - maybe Jim can help?

What I really need for now is to determine the unit vectors for the local axis of a group or component instance entity. Anyone know if this is in the transformation array or of an easier way?

Sorry if I have missed it in the API documentation but could someone point me to where the definition is for each of the 16-elements in the transformation array created by Transformation.to_a (http://code.google.com/apis/sketchup/docs/ourdoc/transformation.html)? I have discovered elements 12,13,14 => x,y,z and was hoping to get the rest without trial and error.

Thanks for your help.

Thanks Adam - I am actually trying your program as you speak as an example of what the display could look like and it looks great but I am not looking for a lighting tool. My equivalent "lighting effect" is created by custom radiation functions that depend on the type of source, the distance from the source, and blockage and are not light sources. I am not lookig for photo realism but for a representation of intensity on surfaces. The essence of my question is: what technique could be used to color small portions of the Sketchup drawing? The resolution I am looking for is typically 30 cm square for drawings that are the size of a building. Is there some way to divide up each face of every entity and assign a color to it based on the result of my "radiation function" as the point.

Perhaps this is part of the infrastructure you mention?

Thanks for your help.

Hi Folks,

I am new to Sketchup and am considering having a Plugin or extension written for an engineering application that "paints surfaces" in a similar manner to lighting tools that display "lux contours". The intensity (represented by a color) of a portion of a surface or face is determined by a calculation similar to lighting intensity with multiple point light sources. The result needs to be part of the Sketchup model and not simply rendered image from one perspective. Not being a 3D rendering or Sketchup expert I wondering if someone could explain to me (or point me in the direction of) the techniques used to "paint" a portion of a surface or face a chosen color using the Ruby API or an extension. Some of the commercial lighting software appears to take advantage of OpenGL capabilities but after scanning through the Ruby API and Googling I am none the wiser.

Thanks for your help.