Parametric modeling in IRONCAD

Even though IRONCAD primarily does not use locked relations in the form of constraints (it does not provide more control or precision to control geometric changes through a parameter table), you can, if necessary, create features, parts and assemblies that are fully or partially controlled by constraints and parameterized dimensions. This is particularly useful for standard table-driven components.

Here we'll go through some basics that are good to know. We start with the fastest way to parameterize a so-called Innovative Part which basically consists of a simple extrusion (Block) that we drop from a catalog in the 3D scene.

‍

Sizebox Driving Parameter

It is quick and easy to add parametric controls to the Sizebox handles that control the size of a feature, part or assembly. By default, the Sizebox handles are primarily displayed on Shape features such as a Block, but it is also possible to add the corresponding Sizebox handles at the part or assembly level.

The video below shows a quick way to use the Sizebox handles to parameterize a so-called Innovative Part which basically consists of a simple extrusion (Block) that we have released from a catalog in the 3D scene. The video also goes through why certain steps are performed in a certain way and what to consider. For example, tips on the names of the parameters you create and how the Anchor Point affects the direction in which a change in size of a parameter takes place.

Tip: At the bottom right, there is a list of chapters, so you can easily jump back and forth between different parts of the video.

Very briefly described, you can right-click on a Sizebox handle to create a parameter that controls the shape of the geometry in that particular direction. The parameter used in the video that controls the shape of the geometry via the parameter table is called the Driving Parameter.

‍

Sizebox Reference Parameter

You can also choose to continue using the differently colored round Sizebox handles "as usual" by being able to drag them freely and instead use parameters to read the current value of the handle. This is called a Reference Parameter and is created in a similar way.

It is therefore important to know whether you want to continue to be able to work with the Sizebox handles ( Reference option) or whether the parameter table should be the one that controls the shape of an object ( Driving option).

Download the model developed in the video.

‍

Parametric Block with Sketch Locks

Here is a very simple example where we combine "free" Sizebox handles with locked dimensions in the sketch for an extrusion. When you pull the outer/larger model, the inner/smaller model is forced to follow.

Another thing that is shown at the end of the video is how to control the precision when dragging "freely" with the Sizebox handles, both in terms of max/min-size but also what size the incremental steps should be.

Download the model developed in the video.

‍

Parameter-driven patterns of features

A simple way to control the number of copies of one or more features in a parametric model is by using a pattern, usually called Pattern. This can be done with TriBall but also via the command Pattern Feature. No matter which way you create patterns of features, you can always control these from the parameter table.

Here is a video without sound that shows how to create a parametric model where the number of certain features is determined by the length of the party.

Download the model developed in the video.

‍

Catalogs of parametric example models

We have produced a large number of parametric models over the years and many of them are available via a catalog called ParametriskaModeller.icc.

That catalog might already be available on your computer, through our add-on installation Swedish Standard Customization. Check via Catalog Open, under the folder for Scene catalogs if the ICC file is available there. Otherwise, you can download it via the link in the text above.

‍

Film series on parametric control in IRONCAD

There are a couple of different series of instructional videos dealing with parametric models in IRONCAD on the training site IronCAD Academy. (Note: These videos have Swedish voice).

Parameter-driven example models

First, we have a series of 7 videos that go through completely different models and ways to parametrically control features in IRONCAD. First up is a simple round washer that is controlled by two circles constrained in the sketch. Remember that you can see all our training videos in the list on the left side.

These 7 videos were created with version 2017 and therefore differ to some extent in terms of menu and catalog content. The round Sizebox handles all have a red color and other colors are also slightly different with e.g. the white instead of black color of the sketch lines and the "gradient" blue-white background.

‍

Parameter-controlled wall cabinet

There is also a series of 15 videos on how to create a fully parameterized wall cabinet in IRONCAD.

‍

Manage your own parametric parts with ICM PROActiveParts

The extension IronCAD Mechanical has several tools for handling parameterized parts. Many of the basic functions found in e.g. the catalog ICM Mech, such as screws, nuts, beams etc. are table-driven standard components and you can easily build your own catalogs with a similar function.

Read more about the PROActiveParts tool in the IC Mech online manual.

‍

Why not use constraints in IRONCAD?

By default IRONCAD does not use constraints as the primary way of controlling the position of either objects in 3D space or lines in the 2D sketch. Instead, the position in 3D space or in the 2D plane is the primary property that controls objects in 3D space or 2D plane and this position is handled with special (usually unique) tools and therefore it is very often sufficient to only select the objects to be changed at the time of the change. However, it is me as a user who controls, so when I think constraints are needed (because nothing else solves a certain situation in a better way), I can apply it where it fits.

However, once you have started using constraints, there is a great risk that you will have to continue placing more constraints until all objects or lines in the sketch are "fully defined". This means that changes can only be made in one or more predicted ways, but no other way is accepted.

For some parts, smaller assemblies and standard components, it can be very smart and useful and save a lot of time when fully predictable changes occur.

However, a recognized disadvantage of constraints is that a unforeseen change cannot be implemented as it may "collide" with one or more existing constraints. You then need to either remove the constraints, with the risk that the model "collapses", or start from scratch with constraints that take into account the change you want to implement.

Since constraints are usually not used or needed in the daily work with IRONCAD, we do not use it in our basic training. But we have a lot of other video material that explains how it can be used in practice and there it is mainly when working with mechanisms that you need to place relationships / constraints between the moving parts.

That said, there are plenty of examples using geometrically parameterized models in IRONCAD, where the position is fully controlled by constraints. However, this is (by and large) only useful for standard table controlled components or reusable assemblies of details that always follow the same completely predictable rules.

‍

The Swedish company Nefab, with hundreds of IRONCAD users around the world, has built countless parametric 3D models of their various types of packaging and uses IRONCAD in a very "broad way". Their "products" produced in IRONCAD are usually completely parameterized via the dimensions that need to be specified in order for the packaging and all its sub-components to have the right number and dimensions. Parameterized - but still easy to change, often via the Sizebox handles.

What is remarkable is that there is not a single constraint or relationship between the 3D models used in everything from customer products handled in the packaging to the "one-off" designed manufacturing machines! That's because constraints themselves don't add any value to these types of models and completely avoid the risk of having to start over!