Maxscript with modfiers

Question

From creating a cube the following code should select the top two triangles, invert that selection and then delete those newly selected faces. So far so good. However, I seem to run into trouble when there’s a modifier (or more) on the base cube.

(
--clear the listener
 clearListener()

 theObj = $

 -- init. an array to collect faces
 selArray = #{}
 invArray = #{}

 append selArray 3
 append selArray 4

 -- get the number of faces in the object
 theMeshCount = theObj.numfaces

 -- invert the array
 for f = 1 to theMeshCount do
 (
 if (selArray[f] == false) then invArray[f] = true
 else invArray[f] = false 
 )

 -- set the face selection in the EMesh
 setFaceSelection theObj invArray

 -- go to modify mode
 max modify mode

 -- select the mesh
 select theObj

 -- add the Mesh Select modifier
 modPanel.addModToSelection (Mesh_Select ())

 -- go to Face level
 subObjectLevel = 3

 --add a delete mesh, preserving the selection
 modPanel.addModToSelection (deleteMesh())
)

So where am I going wrong?

Answer 1

What kind of trouble do you run into, specifically? I've just tried it and if there are no topology-changing modifiers it seems to work as expected. It might be better to get the obj.mesh face count instead so that it would work with primitive objects as well, or maybe you intended to add the modifiers to the bottom of the stack - in that case uncomment the /../ chunks in the code below to make it work on baseobject instead.

Also, inverting the bitarray is as simple as setting its length and putting a minus sign in front of it.

(
    local theObj = selection[1]
    local theMesh = theObj.mesh
    local theMod = Mesh_Select()

    local selArray = #{3..4}
    selArray.count = theMesh./*baseObject.*/numFaces
    delete theMesh

    addModifier theObj theMod /*before:theObj.modifiers.count*/
    setFaceSelection theObj theMod (-selArray)
    max modify mode
    /*modPanel.setCurrentObject theMod*/
    subObjectLevel = 3
    modPanel.addModToSelection (DeleteMesh())
)