Modification Tools

BlastCAD’s geometric kernel includes a complete set of entity modification commands. All modifications are fully undoable with Ctrl + Z.

Table of contents

  1. Selection First
  2. Transformation Tools
    1. Move (MOVE / M)
    2. Rotate (ROTATE / RO)
    3. Scale (SCALE / SC)
    4. Mirror (MIRROR / MI)
    5. Stretch (STRETCH)
  3. Editing Tools
    1. Trim (TRIM / TR)
    2. Extend (EXTEND / EX)
    3. Offset (OFFSET / O)
    4. Fillet (FILLET / F)
    5. Chamfer (CHAMFER / CHA)
    6. Break (BREAK / BR)
    7. Join (JOIN / J)
    8. Explode (EXPLODE / X)
  4. Array Tools
    1. Linear Array (ARRAY / AR)
    2. Polar Array (PARRAY)
  5. Practical Workflows
    1. Cleaning Up a Drive Profile Import
    2. Adjusting Ring Geometry After Placement
    3. Creating a Symmetrical Pattern

Selection First

For most modification tools, you can either:

  1. Select entities first, then invoke the command — the tool applies immediately to the selection.
  2. Invoke the command first — the tool prompts you to select entities interactively.

Selection methods:

  • Click — single entity
  • Left-drag (left to right) — window selection: selects only entities fully inside the box
  • Left-drag (right to left) — crossing selection: selects any entity that the box touches
  • Shift + click — add to/remove from selection
  • Ctrl + A — select all visible entities

Transformation Tools

Move (MOVE / M)

Displaces one or more selected entities by a vector.

  1. Select entities.
  2. Click the base point (reference point for the displacement).
  3. Click the destination point, or type relative coordinates: @dx,dy or @dx,dy,dz.

Rotate (ROTATE / RO)

Rotates entities around a pivot point.

  1. Select entities.
  2. Click the center of rotation.
  3. Click a reference point on the entity, then click the final position — or type the angle in degrees: 45 for 45°, -90 for 90° clockwise.

Use R option to rotate by a reference angle (useful when you know the starting and ending angle explicitly).

Scale (SCALE / SC)

Uniformly scales entities relative to a base point.

  1. Select entities.
  2. Click the base point (fixed point during scaling).
  3. Type the scale factor: 2 doubles the size, 0.5 halves it.

Use R option to scale by reference (from a known distance to a target distance).

Mirror (MIRROR / MI)

Creates a reflected copy of entities across a mirror axis.

  1. Select entities.
  2. Click two points defining the mirror line.
  3. Confirm whether to delete the originals (Y / N) or keep both.

The mirror operation is computed using the reflection formula across the defined axis vector.

Stretch (STRETCH)

Moves a portion of entities while keeping endpoints outside the selection fixed. Unlike Move, Stretch reshapes connected geometry.

  1. Use crossing selection to select the vertices you want to stretch.
  2. Specify the base point and displacement.

Entities fully inside the selection window move as a unit. Entities crossing the boundary are stretched.

Editing Tools

Trim (TRIM / TR)

Removes segments of entities that cross a selected cutting edge.

  1. Select the cutting edge(s) (one or more lines, arcs, or polylines), then press Enter.
  2. Click the segment you want to remove (the portion on the side of the cut).

BlastCAD computes the exact parametric intersection between the selected entity and the cutting edge, splits the entity at that point, and removes the clicked portion.

Edge Select All: Press Enter immediately without selecting cutting edges to use all visible entities as potential cutting edges.

Extend (EXTEND / EX)

Projects an entity’s endpoint to meet a boundary edge.

  1. Select the boundary edge(s), then press Enter.
  2. Click the endpoint of the entity you want to extend.

BlastCAD computes the projected trajectory of the entity and extends its terminal vertex to the exact collision point with the boundary.

Offset (OFFSET / O)

Creates a parallel copy of a line or concentric copy of a polyline/circle at a specified distance.

  1. Type or click the offset distance.
  2. Click the entity to offset.
  3. Click the side to place the offset copy.

For a line $AB$, the offset $A’B’$ is computed by translating both vertices along the perpendicular unit normal vector by the offset distance $d$:

\[A' = A + d \cdot \hat{n}, \quad B' = B + d \cdot \hat{n}\]

For polylines with multiple vertices, each segment is offset independently and the resulting segments are rejoined at correct intersection points to maintain geometric continuity.

Fillet (FILLET / F)

Rounds the corner between two lines with a circular arc of a specified radius.

  1. Type the fillet radius (R, then value).
  2. Click the first line, then the second line.

If radius = 0, Fillet trims/extends the two lines to their exact intersection (sharp corner cleanup).

Chamfer (CHAMFER / CHA)

Creates an angled cut between two lines, defined by two distances from the corner.

  1. Type distances (D, then first distance, then second distance).
  2. Click the first line, then the second.

If both distances = 0, Chamfer trims/extends to the intersection (same as Fillet at radius 0).

Break (BREAK / BR)

Splits an entity into two separate entities at one or two specified points.

  • Break at point: BR → click entity → type @0,0 → result is one entity split into two at the clicked point.
  • Break between two points: BR → click entity → click second break point → the segment between the two points is removed.

Join (JOIN / J)

Merges multiple collinear line segments or adjacent arc segments into a single polyline entity. All segments must be end-to-end connected within a small tolerance.

Explode (EXPLODE / X)

Breaks a compound entity (polyline, block, rectangle, or donut) into its individual constituent segments. Useful when you need to trim or offset individual segments of a polyline independently.

Array Tools

Linear Array (ARRAY / AR)

Creates a rectangular grid of copies of the selected entities.

Required inputs:

  • Number of rows and columns
  • Row spacing (Y direction)
  • Column spacing (X direction)

Polar Array (PARRAY)

Creates a circular arrangement of copies of the selected entities around a center point.

Required inputs:

  • Center point of the array
  • Number of items
  • Angle to fill (default 360° for a full circle)
  • Whether to rotate each item as it is copied

Practical Workflows

Cleaning Up a Drive Profile Import

  1. Import the Surpac .str file (drive boundary arrives as polylines).
  2. Use TRIM to remove overhanging segments outside the stope envelope.
  3. Use JOIN to merge split segments back into a single continuous polyline.
  4. Use OFFSET at the design burden distance to generate the ring plane boundary.

Adjusting Ring Geometry After Placement

  1. Select the ring’s hole lines in the viewport.
  2. Use MOVE with a relative coordinate to shift the entire ring along the baseline.
  3. Use ROTATE to adjust the dip angle of individual holes.
  4. Use EXTEND to bring hole toes to the target DTM surface if they fall short.

Creating a Symmetrical Pattern

  1. Draw one half of a symmetric bolt/anchor pattern.
  2. Use MIRROR across the centerline to create the other half.
  3. Use ARRAY (polar) around the center to create a radial distribution.

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