CAD: How to model complicated smooth shapes?

Question

I'm somewhat new to CAD and don't exactly know what terms to look for. So far every model I've seen or made is essentially built from straight lines and circle segments or other "primitive" shapes. What I want to know is, what the approach for something more complicated is while still following constraints and and relationships to other things of the model, for example the shape of an aerodynamic car door or something that looks somewhat sculpted.

As a quick example I've made a simple model in blender. The red object is a stretched sphere with some deformation. The green one is just the stretched sphere with no other edits for comparison.

In blender this is easy since you can just edit the polygons themselves. The big drawback is of course that this process is not non-destructive. If I wanted to change the resolution of the individual polygons later, I'd have to start over.

So my question in short is what method would be used here in a CAD software? Personally I'm using Solid Edge but I'm guessing different programs behave similarly. Perhaps you can use bezier curves to define the shape? Or something else?

Answer 1

You can use modifiers.Modifiers are automatic operations that affect an object in a non-destructive way. With modifiers, you can perform many effects automatically that would otherwise be too tedious to update manually (such as subdivision surfaces) and without affecting the base geometry of your object. They work by changing how an object is displayed and rendered, but not the geometry which you can edit directly. You can add several modifiers to a single object to form The Modifier Stack and Apply a modifier if you wish to make its changes permanent. Modify

These are tools similar to the Deform ones (see below), however, they usually do not directly affect the geometry of the object, but some other data, such as vertex groups.

Generate

These are constructive/destructive tools that will affect the whole Topology of the mesh. They can change the general appearance of the object, or add new geometry to it…

Deform

Unlike Generate ones above, these only change the shape of an object, without altering its topology.

Simulate

Those represent physics simulations. In most cases, they are automatically added to the modifiers stack whenever a Particle System or Physics simulation is enabled. Their only role is to define the position in the modifier stack from which is taken the base data for the simulation they represent. As such, they typically have no attributes, and are controlled by settings exposed in separate sections of the Properties.

Use of active modifiers

A modifier in the stack can be selected to mark in as Active, the active modifier displays an outline around the modifier’s panel. To set an active modifier, select an area of the modifier’s panel background, the modifier’s icon, or, select a modifier in the Outliner.

The active modifier is used by the Geometry Node Editor to determine which node group is being modified.