Adaptivity in Autodesk Inventor is something that appears frequently, but is rarely used appropriately. Using adaptivity generally means that certain aspects of a part will change as changes occur in the constrained assembly; the part will adapt to fit the assembly.
This is very useful when parts such as springs, rubber or any other flexible components need to be presented as a part of an assembly. Personally, I do not use it very often, but it does wonders when I need to display the movement of suspension parts in a car.
In order to make a part flexible, the sketch of that part must change proportionally to the change of the position of certain components in the assembly. This is where adaptivity comes in.
Let me clarify this with a small tutorial:
How to make an adaptive spring
1. First, let’s open a simple assembly of a damper:
This is a simple, two component assembly where the top of the damper can move up and down, just like any ordinary shock absorber.
3. Make a plane on top of the bottom (blue) ring, and project another plane above the first. I chose the distance of 130mm.
4. Create a sketch for the spring. Make sure to place the sketch on the assembly of the damper. Project the two created planes on to the sketch. The projections of the planes will move when the planes are moved. This is the one of the key elements for successfully making a component adaptive.
5. Add a dimension to display the distance between two projections. Inventor will ask you if you would like to create a driven dimension (this happens because the two projections are fixed at the moment) – click Accept.
6. Now, create a base for the spring on the same sketch. You will need a center line and a circle at the bottom. The diameter of the coil that I chose was 10mm.
7. Click on ‘Coil’ feature and go to the ‘Coil Size’ tab. Select Revolution and Height. Click on the arrow next to ‘Height’ and select ‘Measure’. Now select the dimension that indicates the distance between the two projected planes. (I also included a “-10” (the diameter of the coil) to my height in order for the spring not to merge into the top ring of the damper). This will allow the coil to be compressed, when the two projections move and change the created dimension. Type in the selected amount of revolutions you wish to have. Click OK to produce a coil.
8. Make the two planes adaptive by right clicking on them and turning on ‘Adaptive’
9. Constrain the top plane to the top blue ring of the damper.
10. Constrain the bottom ring to the top plane. Make sure you tick the ‘Predict Offset and Orientation’ box. Click OK. Usually, this constraint would not make sense, but remember, we want the spring to compress.
11. Right click on the constraint that was just created, and select ‘Drive Constraint’ option.
12. Expand the pop-up box, and tick the ‘Drive Adaptivity’ box. Type in the ‘Start’ and ‘End’ dimensions, press play and enjoy the view of a damper that is being compressed along with the spring.
The ‘Drive Constraint’ dialog can be used to record the motion in the viewport. Alternatively, the model can be brought to Inventor Studio, where the constraint can be driven and recorded in a scene.
NOTE: You will not be able to interact directly with the assembly (I.e. move the damper by clicking and dragging) in the viewport. In order to do that, you will have to suppress the created constraint.
Adaptivity can also be applied for other components. For example, you can create a balloon, which gets inflated (increases in diameter with an increase of the distance between the planes) The key is to understand how adaptivity works in order to use it, and I hope that this tutorial helped at least a tiny bit.
While adaptivity is used in many different aspects of the Inventor interface, workflows like I’ve detailed above can be time consuming and are sometimes an unforgiving process (one small constraint, and the assembly fails). However very often the results are worth the hassle