About Built-in Slots

The slot built-in geometry is a specific feature computing a contour for an opening to allow the profile to pass through a plate or another profile. It is defined by a curve produced by a set of parameters and faces extracted from the profile, with some conventions.
The following topics provide a detailed information about slot parameters:
 

Slot Parameters
  One or more than one parameters define a straight line or a circle. The intersection of straight lines and circles are connected in a predefined sequence to generate a contour.
  • Auxiliary parameters are the parameters which cannot exist alone. They are always interpreted with some other parameters.
  • Collaborative parameters are the parameters which exist in a set. The absence of even one parameter from the set affects the other parameters and makes them meaningless.
 

Parameters Defining a Straight Line or Distance
  The name of straight linear parameters starts with letter D (distance).
There are 12 parameters that define straight lines with respect to horizontal (H) or vertical (V) linear dimensions of an I-section for example.
The four faces (highlighted in red color) are used to calculate the distances.
  • Five of these twelve parameters are related to top flange (MoldedFlange2): DTT, DTR, DTBR, DTBL (symmetry of DTBR/V), DTL (symmetry of DTR/V).
  • Five of these twelve parameters are related to the linear dimensions of bottom flange (MoldedFlange1): DBTR (symmetry of DTBR/H), DBTL (symmetry of DTBL/H or symmetry DBTR/V), DBL (symmetry of DBR/V or symmetry DTL/H), DBB (symmetry of DTT/H), DBR (symmetry of DTR/H).
  • Two of these parameters define lines on both sides of web (WebInner+ and WebInner-): DR, DL (symmetry of DR/V).
 

Parameters Defining a Circle 
  A radius parameter exists only with two additional parameters that define the center for the circle. Thus, a circle defining parameters exists in a group of three and constitutes a set of collaborative parameters.
The name of radius parameters starts with letter R (radius). The parameters defining center coordinates start with H (if it defines horizontal coordinate) or with V (if it defines vertical coordinate) followed by the name of radius.
There is one radius parameter corresponding to each corner. Twelve circles (hence arcs) can be defined using 36 parameters. 
  • At top flange:
    RTTR  HRTTR  VRTTR 
    RTTL  HRTTL  VRTTL
    RTBL  HRTBL VRTBL
    RTBLW HRTBLW VRTBLW
    RTBRW HRTBRW  VRTBRW
    RTBR  HRTBR VRBTR
  • At bottom flange:
    RBTLW  HRBTLW  VRBTLW 
    RBTL  HRBTL   VRBTL  
    RBBL  HRBBL  VRBBL
    RBBR HRBBR  VRBBR 
    RBTR  HRBTR   VRBTR  
    RBTRW  HRBTRW   VRBTRW  
 
When using circle parameters, you need to know the face from which the horizontal and vertical coordinates are computed. For example, RTBR is located at right of face right, and below the top face. That means the coordinates are computed positively from these two references. If you want to locate RTBR above top face, then you should use negative value for the vertical coordinates.
 

Straight Lines at an Angle to Section Linear Elements

  An auxiliary angle parameter along with one of the parameter is used to create a slant line. The names of auxiliary angle parameters start with A. There is a one-to-one correspondence between parameters of distance and these auxiliary parameters. Thus, there are twelve angle parameters corresponding to each linear parameters defined above.
  • Angle parameter for top flange offset distance: ADTT ADTR ADTBR ADTBL ADTL.
  • Angle parameter for bottom flange offset distance: ADBTR ADBTL ADBL ADBB ADBR.
  • Angle parameter for both sides of web: ADR ADL.
 
The angle is measured in:
  • Counterclockwise for all right vertical lines and all horizontal lines.
  • Clockwise for all left vertical lines.

Snipe Straight Lines

  There are two offset linear parameters corresponding to each corner. These parameters always exist in pair. A pair defines a snip at a corner. If a pair of parameters is defined at a corner, a radius parameter cannot be defined at the same corner and vice versa.
One trim parameters defines end of a line defined by an offset parameter.
 

Super Curve of Parameters
  The curve is computed from the parameters, proceeding with an anti-clockwise direction. All the above parameters (also called private parameters) used to build the contour are created in a reference slot object.

It is possible to make the contour parametric to maintain continuity and to ensure symmetry by adding new parameters to drive the others. This method requires formulas between the private parameters, and also adds new parameters, named public parameters. Those formulas are added in the slot reference.
 

About Slot Type and Profile Type
   
  In the catalog, there are three profile types:
  • Tee
  • Bulb
  • Angle

Here we are considering four slot types. There can be 'n' number of possibilities of slot type.

  • RECT
  • BOOT
  • BULB
  • FLAR
Every slot type should be associated with each profile type. There exist 12 combination:
  • RECT_Tee, RECT_Bulb, RECT_Angle
  • BOOT_Tee, BOOT_Bulb, BOOT_Angle
  • BULB_Tee, BULB_Bulb, BULB_Angle
  • FLAR_Tee, FLAR_Bulb, FLAR_Angle
For each combination, you can create a reference .CATPart and each part will have formulas to define relationship between private and public parameters.