VariCAD 3D Mechanical Modeling: Part Design, Assembly, and 2D Drawing Generation

VariCAD 3D Mechanical Modeling: Part Design, Assembly, and 2D Drawing Generation

VariCAD is a 3D mechanical CAD application developed in the Czech Republic, optimized for mechanical engineering and product design. It provides parametric 3D modeling, assembly design, and automatic 2D drawing generation at a competitive price. This guide covers the complete workflow from sketch to finished drawing.

Interface Overview

VariCAD's interface is task-oriented:

• Menu bar: File, Edit, View, Tools, 3D, 2D, Assembly, Sheet Metal, etc.
• Toolbar: Left side, context-sensitive tool buttons
• Command line: Bottom, accepts typed commands and shows prompts
• Tree view: Right side, shows assembly structure and feature history
• Status bar: Cursor coordinates, snap settings

Key Concepts

VariCAD uses a hybrid approach:

• 3D Mode: Create and edit 3D solids and assemblies
• 2D Mode: Create 2D drawings (either from 3D or standalone)
• You switch between modes using the tabs at the bottom of the screen

Sketch-Based Part Design

Creating a Sketch

1. Select a plane (XY, XZ, or YZ) or a planar face on existing geometry
2. Tools > Sketch > New Sketch
3. Draw 2D geometry on the sketch plane:
   • Lines, arcs, circles, rectangles, polygons
   • Use snapping to existing geometry
4. Apply dimensions and constraints to fully define the sketch

Sketch Constraints

VariCAD supports sketch constraints:

• Horizontal/Vertical: Constrain line direction
• Parallel/Perpendicular: Constrain line relationships
• Tangent: Constrain line-to-arc or arc-to-arc
• Concentric: Constrain circle/arc centers
• Equal: Constrain equal lengths or radii
• Symmetric: Constrain symmetry about a line
• Dimensional: Driving dimensions (linear, angular, radial)

Fully Defining Sketches

A sketch is fully defined when all geometry is constrained and dimensioned. VariCAD shows:

• Green: Fully constrained
• White/Black: Under-constrained (can be dragged)
• Red: Over-constrained or conflicting

Creating 3D Solids from Sketches

Extrusion

1. Create a closed sketch profile
2. Tools > 3D > Extrude
3. Select the profile
4. Specify:
   • Distance: Extrusion depth
   • Direction: Normal to sketch or custom
   • Draft angle: 0 for straight, or angle for tapered walls
   • Symmetric: Extrude both directions from sketch plane

Revolution

1. Create a sketch profile (cross-section)
2. Draw or select a revolution axis
3. Tools > 3D > Revolve
4. Select profile and axis
5. Specify angle (360° for full, or partial)

Sweep

1. Create a sketch profile (cross-section)
2. Create a path (sketch or 3D curve)
3. Tools > 3D > Sweep
4. Select profile and path
5. The profile is swept along the path

Loft

1. Create multiple sketch profiles on different planes
2. Tools > 3D > Loft
3. Select profiles in order
4. The solid transitions between profiles

Boolean Operations

Adding Material (Union)

1. Tools > 3D > Boolean > Add
2. Select the base solid
3. Select the solid to add
4. They merge into one solid

Removing Material (Subtract)

1. Tools > 3D > Boolean > Cut
2. Select the base solid
3. Select the tool solid (cutter)
4. The tool volume is removed

Intersection

1. Tools > 3D > Boolean > Intersect
2. Select two or more solids
3. Only the overlapping volume remains

Feature Editing

Fillet

1. Tools > 3D > Fillet
2. Select edges (or faces to fillet all edges)
3. Specify radius
4. Constant or variable radius

Chamfer

1. Tools > 3D > Chamfer
2. Select edges
3. Specify distance and angle (or two distances)

Hole Features

1. Tools > 3D > Hole
2. Select a planar face
3. Specify:
   • Hole type: Simple, counterbore, countersink, tapped
   • Diameter: Hole diameter
   • Depth: Through or blind
   • Position: Click or use sketch dimensions

Shell

1. Tools > 3D > Shell
2. Select the solid
3. Specify wall thickness
4. Select faces to remove (open faces)

Rib

1. Tools > 3D > Rib
2. Select a reference plane
3. Draw the rib profile (sketch)
4. Specify thickness and direction
5. The rib is created and merged with the base solid

Assembly Design

Creating an Assembly

1. Tools > Assembly > New Assembly
2. Insert parts:
   • File > Insert Part from File
   • Or select existing parts in the current document
3. Each part appears in the Assembly Tree

Assembly Constraints

VariCAD supports assembly constraints:

• Coincident: Two points or axes are coincident
• Concentric: Two cylindrical faces are concentric
• Planar: Two planar faces are coplanar (with optional offset)
• Parallel: Two faces or edges are parallel
• Perpendicular: Two faces or edges are perpendicular
• Tangent: Two faces are tangent
• Distance: Maintain a specific distance between faces
• Angle: Maintain a specific angle between faces

Applying Constraints

1. Tools > Assembly > Constraints
2. Select constraint type
3. Select the first face/edge on part A
4. Select the second face/edge on part B
5. Specify offset or angle if needed
6. The parts move to satisfy the constraint

Checking Interference

1. Tools > Assembly > Interference Check
2. Select all parts or specific pairs
3. VariCAD reports interfering volumes
4. Interfering solids are highlighted in red

Exploded View

1. Tools > Assembly > Exploded View
2. Select parts to explode
3. Specify explosion direction and distance
4. The assembly shows separated components
5. Save the exploded view for drawing generation

2D Drawing Generation

Creating Views from 3D

1. Switch to 2D mode
2. Tools > 2D > Views from 3D
3. Select the 3D part or assembly
4. Choose view types:
   • Standard: Front, Top, Right, Isometric
   • Section: Full, half, offset section
   • Detail: Enlarged view of a specific area
   • Exploded: From saved exploded view
5. Place views on the 2D sheet
6. Views are linked to the 3D model — updating the 3D model updates the views

Section View Creation

1. Tools > 2D > Section View
2. Select the parent view
3. Draw the section line (cutting plane)
4. Specify viewing direction
5. The section view is generated with hatching

Dimensioning 2D Views

1. Tools > 2D > Dimension
2. Select dimension type (linear, angular, radial, etc.)
3. Click on geometry in the view
4. Place the dimension
5. Dimensions are associative — they update if the 3D model changes

Bill of Materials (BOM)

1. Tools > 2D > BOM
2. Select the assembly
3. VariCAD generates a parts list with:
   • Item number
   • Part name
   • Quantity
   • Material
   • Custom properties
4. Place the BOM table on the drawing
5. Balloon numbers are automatically linked to the BOM

Export

STEP (AP203/AP214)

File > Export > STEP — for CAM, FEA, and other CAD systems

STL

File > Export > STL — for 3D printing

DWG/DXF

File > Export > DWG/DXF — for 2D drawing exchange with AutoCAD

IGES

File > Export > IGES — legacy CAD exchange

Conclusion

VariCAD provides a complete 3D mechanical design workflow: sketch-based part design, boolean operations, feature editing, assembly design with constraints, and automatic 2D drawing generation with BOM. The parametric link between 3D models and 2D drawings ensures consistency — change the 3D model and the drawings update automatically. While not as feature-rich as SolidWorks or Inventor, VariCAD covers the essential mechanical design workflow at a significantly lower price point, making it a practical choice for small to medium engineering firms.