Why a 3D Sketch?
Contents
3D sketches can be very useful for certain commands in Solidworks:
- It can be used in Weldments to insert structural members along a 3D frame.
- In the making of Guide Curves for Sweeps and Lofts, it can be very useful to use a 3D sketch to create the required path.
- 3D sketches are also useful when working with Tube and Cable routing or when modeling ropes as a 2D sketch can’t always accurately be used to describe their paths.
- 3D sketches can be used when there is no face or plane present where you want to start a 2D sketch.
- Using the 3D sketch option in Hole Wizard allows you to create the same type of holes on multiple faces and prevents you from making multiple 2D sketches and Hole features. Also, In drawings, they show up grouped as one keeping the drawing neat and clean.
3D Sketch inherits almost all the capabilities of the normal 2D sketch and can be used to create most of the features that you create using 2D sketches. (Some exceptions include Revolves). All the existing relationships that you can have in a 2D sketch are still available (but some of these relationships may have additional options or requirements in a 3D sketch). So you might be thinking why don’t we use it all the time then. Well, because 3D sketches can get a little tricky to control.
3D Sketching Tools
3D sketch has some additional tools in its arsenal for you but also lacks a few as compared to the 2D sketch. Let’s take a look at them:
- You cannot use Ellipse, Slot, Polygon, or Text in 3D Sketch.
- Offset Entities and Patterns (Linear Pattern and Circular Pattern) are also unavailable in the 3D sketch.
- Spline on Surface is only available in 3D. It is a type of Spline that allows you to construct a spline on any surface.
- Offset on Surface tool allows you to offset model edges and faces onto surfaces.
- Additional Relations and Dimensions gets available to you in a 3D sketch.
How To Create a 3D Sketch?
To initialize a 3D Sketch, select 3D Sketch from the dropdown menu under Sketch Tool available in Sketch Tab or go to Insert -> 3D Sketch.
When creating 3D sketches, pay attention to your Cursor and Space Handles. The cursor shows the axes comprising the plane you are currently working on and the space handle displays the global coordinate system on the point where you last clicked and the arrows highlighted in red show the two axes creating the plane you are currently working on. These two items will help you to orientate the geometry.
To switch orientations, use the Tab key to rotate through the three i.e. X-Y, Y-Z, and Z-X planes.
3D Sketch Plane is an option provided to help you take advantage of the simplicity of the default 2D sketching process in a 3D sketch. A 3D Sketch Plane is an ordinary 2D plane that only exists inside the 3D sketch. When it is activated, you can only sketch on that plane and hence you will get a similar experience to working in a 2D sketch. 3D sketch planes are also very useful when you are giving dimensions to your sketch.
To add a 3D sketch plane go to Tools -> Sketch Entities -> Plane or select the Plane icon available in the toolbar. To use an existing plane in a 3D sketch, select the plane and go to Insert> 3D Sketch On Plane or you can also double click on an existing plane if you are already inside the sketch. If you want to deactivate that plane, double click on the graphics area, and the plane will be deactivated and you will be returned to the normal 3D sketch.
Tips and Tricks:
1. It is always recommended that you use references to create a 3D Sketch. You can either use 2D sketches, curves, and reference geometries as references, or you can use a 3D model that you have already made and use its edges, vertices, and faces as reference geometry.
Let’s take an example. Suppose we want to create the 3D sketch shown below.
You can start creating the 3D sketch but as you will proceed with your sketch you will struggle while giving dimensions, making fillets, and sometimes end up over-defining the sketch, or not sketching on the correct plane.
What you can do instead is you can create a 3D geometry using simple 2D sketches whose edges will represent the lines and curves of the 3D sketch. Once you have your desired shape with the correct dimensions, you can use this solid body to create the 3D sketch.
To use this 3D geometry, start a 3D sketch and then either convert its edges with help of the Convert Entities tool present in the Sketch Toolbar or use its vertices or edges for reference while creating your own 3D sketch.
Another method is that you create enough 2D sketches and then use them as references to create the 3D sketch.
3. Use the Sketcher Triad or Move Entities to move 3D sketch entities:
To use the Sketcher Triad right-click in the graphics area during 3D Sketching and select Show Sketcher Triad.
The triad will become visible in the bottom-right corner. Now select the entity that you want to move and drag the sketcher arrows to move them. This helps prevent the entities from moving in unwanted directions.
Additional Tools Available in 3D Sketch
1. Spline On Surface:
This tool allows you to create a Spline on any kind of surface whether it be a flat or a curved one. You can access this tool by clicking on the drop-down icon present along with the Spline tool in the Sketch toolbar.
2. Offset on Surface:
1. Click on Offset On Surface tool available in the Sketch tab or .
2. Now select the Offset Type:
- Geodesic Offset: It creates an offset distance that is the shortest possible distance between the selected edge and the resultant offset entity while taking the curvature of the surface into account.
- Euclidean Offset: It creates a linear offset distance between the selected edge and the offset entity that does not include the curvature of the surface.
3. Define the Offset Distance and optionally, check Reverse to reverse the direction of the offset entity. Use Make Offset Construction if you want to use the offset geometry as a reference.
3. Additional Relations and Dimensions
In a 3D sketch you will find Along X, Along Y, Along Z, Normal, On Plane, On Surface, Parallel YZ, and Parallel ZX addition to the ones already present in the 2D sketch.
Some relations are changed in 3D Sketch such as Mirror. You will need a plane to use the mirror command in 3D Sketch as compared to a line or edge in a 2D sketch.
There are also various dimension types available in 3D sketches. The cursor will show you which dimension type is active. Absolute which measures the absolute distance between two points/lines and along X, along Y, and along Z which measures the distance between two points/lines along with the X-axis, Y-axis, and Z-axis respectively. You can cycle through these using the Tab key on your keyboard.
