Design Intent

From skeletal model to final product

A parametric design software not only helps creates a 3D model of the part / product for manufacturing, but also captures the relationship between the different features that are used in their creation. It is for this reason the tool is considered extremely powerful. The relationship between different features is captured, so that a change made to certain feature would automatically update other features that are related to it in some way. So in case if you want to build a robust model / design that's easily editable and make future changes easier. It's important that some amount of thought is given to the intent of the design.

So basically, design intent is forethought that's given before you embark on the process of detailed designing.
In the sketch exercises that we have done so far, we made sketches keeping in mind the dimensions that were provided. We had no idea about the function of the different features and how they are associated with others. However, when a new product development takes place, we may start from scratch and it would be required to make sketches for a product that does not yet exist. So, it is at this point, we may need to keep in mind the intent of our part and associated products, and while keeping this in mind we may make sketches and proceed with the modelling.

Modular chassis platform

Design intent that is captured in case of new product design is done by using the top down design approach. In this interdependencies, skeleton model, knowledge parameters etc. are captured. It could be a skeleton sketch through which you want to capture knowledge or the basic framework and feature relationship that lets you test various design scenarios and changes easily. For example, before making a detailed design of all the parts of a motorcycle, you may define a simple line sketch having built into it the steering geometry of the motorcycle, its wheelbase, engine inclination, rear suspension geometry etc. All other parts such as handlebars, chassis, footpegs, fuel tank, seat etc. may make use for this sketch and may be driven by it in such a way so that any modification does not require or make the product unmanageable and changes may be easy to apply. This is an example where a design intent is applied in a very broad area. Such a broad process may also be used to create a modular chassis platform for the purpose of creating several products without the need for extensive modification. 

A relationship captured through parametric design is robust
even after changes have been applied 

How does the design intent help?

When a basic model in the form of skeleton has been formed with knowledge like what will be the wheelbase and other critical aspects. The development can then move on to detailed design where work on individual components may start. When the interface between different parts in an assembly has been recognized, feature creation becomes easier. Intent of the different features within the part can also be recognized and associated in a logical manner to create the final geometry. Design intent can be really broad or it may even be applied in a very narrow respect. An example of design intent application may be where a certain feature is driven by a part dimension. For example, A solid rod of a certain diameter has through hole. And you may drive the hole diameter with a constraint that obeys a certain relationship with the diameter of the shaft. For example, the hole may be 1/3rd the value of the diameter, so such intent can be built into the design itself.

It also helps concurrent modelling, communication and aids in spreading the project across all organization levels that may need it. And, it saves time through faster implementation of changes.