SolidWorks Sketch Dimensioning Tips
Sketching it typically the basis for your models within Solidworks, but let’s be honest… it’s not always the most glamorous! I’m a firm believer that there is a fine line between efficiency and laziness. In your quest to do less work you actually become more efficient. So here are a few Solidworks Sketch Dimensioning tips to get you less work while you are sketching. [Also take a look at my post 10 Solidworks Sketching Tips You Want to Learn]
Dimension, but Only When I Want It Too
I am not one to do something twice, that is why I love the option to apply dimensions as I am defining the size of my sketched objects. Many of the sketch creation features (including lines, circles, rectangles, etc) include an option to Add dimensions. What this means is as you sketch Solidworks applies dimensions.
However, I only want dimensions when I actually specify the object size…. which is where the options come to the rescue. [Tools > Options > Sketch].
By checking Enable on screen numeric input on entity creation, text boxes will appear on the screen as you are sketching so that you can specify the size of the object on the screen. By enabling Create dimension only when value is entered Solidworks will only convert your specified values into dimensions… exactly the workflow I want!
Other dimensioning tips…
- If the dimension is bouncing between the types… say horizontal to vertical to normal… as you move your mouse around the screen, right-click to lock the dimension orientation.
- To dimension to the virtual intersection of a rounded corner, first select the two lines and click Point to locate a point at the intersection… then dimension
- When dimensioning to a centerline continue moving the mouse to switch from the linear dimension to dimensioning the diameter
Those Pesky Arcs and Circles
On the topic of sketch dimensions, when dimensioning between arcs and circles hold Shift as you select objects. By holding Shift, Solidworks creates dimensions tangent opposed to snapping to the center point.
To dimension the arc length, pick the two end points of the arc then the arc itself. For the arc opening angle, pick the two endpoints and the arc center point and pick the location of the dimension.
Fully Define Sketch (aka Auto Dimension)
The Display / Delete Relations panel provides two great tools for working with your sketches. [Not saying Add Relation isn’t great, it’s just you don’t really need it with all the onscreen, in-context, heads-up options available now-a-days]
Fully Define Sketch attempts to do exactly as advertised…. it fully defines your sketch. It does so by applying what it deems as missing dimensions and relationships. What really makes this tool so powerful are the options. In the first section (Entities to Fully Define) notice that you can select all the objects (entities) in the sketch or be specific and only work with the currently selected objects. Clicking Calculate applies the missing relationships and dimensions.
Within the Relations section select the relationships you wish to have applied. Remember that by deselecting relations you may limit the software from fully defining the sketch. However, there are many times that certain relations cause the wrong (undesired) results. The great thing here is that you can always deselect relations, calculate, and if needed re-enable the relations and calculate again.
Use the Dimension section to define the type and placement for the generated dimensions. This includes Baseline, Chain, and Ordinate types and Above, Below, Right, and Left of the sketch for placement
A tip for using Fully Define sketch is to dimension and/or add relations to key sketch components BEFORE using the feature. Why? Then you are guaranteed to have the key areas defined and not leave it to the software to figure out. Use Fully Define sketch to take care of the clean up, finding the “open” entities and applying the missing details.
There will be times when you need to make modify to your sketch, but you can’t because the relationships are preventing you from making the desired changes. Consider using Display / Delete Relations select and delete multiple relations in one operation. As you select the relation in the list, it cross-highlights in the graphics window.
The Relations filter provides a quick method for limiting the list for just relations of a certain type
Another neat option, one I haven’t had that many opportunities to use, is the Replace option. Located in the Entities section, you can replace the selected entity with another that you have selected in the graphics window. If it doesn’t work SolidWorks will tell you so by showing a status of invalid.
Last tip for today is to try the new Instant2D feature added in SolidWorks 2016. With Instant2D active when you select the dimension value you can modify its value in the onscreen input box.
You can also use the Instant2D Rulers to make constrained adjustments of the existing dimensions. After selecting the dimension, click-and-drag the dimension handle located at the end of the leader. The Instant2D handle automatically appears. As you drag over the ruler, your cursor snaps to the lines, meaning you can make small incremental changes (small ticks) or large incremental changes (large ticks). When you release the mouse the sketch updates.
Feature Image “Sketch” by Ian Normand