CADchUP Profiles CUPRO

This app is currently not available. We are busy coding and doing our best to make it available as soon as possible. Current activities are developing a basic version. It is our intention to offer this for free and offer a table driven version for a typical app price.

This application assists you in drawing 2D or 3D profiles, based on both free and standardized profiles. You can choose between tables or custom dimensions. As a bonus it contains an additional gear, joint and mathematics section.

This parametric app can be a huge time saver and is a "must have" for engineers.

  • For an introduction and in depth help go here: CUPRO_Help

  • A (temporary) working paper for communication and details: wp_geometry



Mathematic shapes


With so many international standards, there are many shapes for profiles. This page gives an overview.

Shapes and designation

What is an I- and what is a H-profile? It is subjective, Do I-profiles have a larger height / width ratio? Or a different web thickness / flange thickness compared to H-profiles? A senseless discussion. And when is an I-profile a beam or a bearing pile or a column? An engineer is free to use a column as a beam. What is a beam? The association in our mind is a horizontal piece of steel, able to resist vertical forces.

Technology changes too. I's were traditionally made by rolling, milling hot steel in a desired shape. Today we see them welded too, composed from sheet metal. They used to be rolled by using low performance steel with a nice price tag. Nowadays high performance steel is an option too, in order to reduce weight, tensile strength is increased. And if you want stainless steel, you can get it. Even hollow I's are introduced to the market.

So we put everything together and designate it all as a family of I-shapes or I-profiles. That includes for example W-beams (Wide flange), Rolled Steel Joists, Double T's and even wooden shapes.

Horizontal parts of the "I" are called flanges and the vertical part between the flanges is called the web. Concerning shapes, there are major differences in principles: There are tapered and parallel flanges. Minor differences can be radii or production details like welded I-beams.

A similar approach can be applied to Channels. These are rolled. But a UNP is a channel too, where "U" stands for the shape. Cold U-profiles are common. Cold C-profiles typically have, compared to U-profiles, two extra flanges. So we end up with a family of U-shapes with three planes (two flanges and one web) and a family of C-shapes with, compared to U-shapes, two extra flanges, totalling five planes. Though tempting, channels are better not called C- but U-shapes.

Standards and designation

Every standard covers many dimensions and shapes. A standard also covers a market area. US ASTM-beams are not a logical choice in Europe, just as Russian GOST-beams are not practical in Great-Britain. A standard acts as a main group identifier for choosing a product for a specific geographic area. But, with the world becoming smaller, the offer in terms of variety is increasing.

Under each standard, designation varies. Russia based GOST uses straight forward numbers, Britain based BS uses parameters with lots of digits (historically from inches to metric). Designating a GOST-profile is very easy while designating BS-profiles requires serious typing skills.

Designations and CAD

This application distinguishes itself in that it is for power users and that it contains extremely large amounts of data (thousands of standard profiles). The program also haves special functions for mathematics, joints and gears. During the making of this program, one of the most difficult things was to properly classify shapes. Previously this was not so difficult, you picked up a DIN standard and you had everything together. But the world is changing rapidly. An engineering company in India designs for a US client with other standard profiles than for a customer in Europe. And if you walk into a supermarket, the offer is much bigger than two decades ago. For metals, this also applies. You can order a warm rolled IPE profile, but stainless steel or aluminium are no problem, if necessary with custom sizes.

Classification of shapes

Classification based on production methods

Hot rolled, cold rolled, extruded, that was how you described a shape and what is still prevalent. U sections illustrate this well:


  1. Traditionally, hot-rolled. Nowadays also as extrusion. To avoid tensions, machining is an (expensive) option.
  2. As 1, the difference is that the walls are parallel but bending is not possible because of the corners.
  3. A constant thickness makes bending possible but extrusion can reduce costs. Hot rolling may also be interesting.
  4. As 2. with the ability to use laser-fusing.

For an engineer it does not matter how it is made, as long as the desired specifications are met. The reasons for an engineer to fall back on naming a production methods are:

  • The naming of a production method helps to make a responsible choice in order to control the cost price. For example, the milling of an I-profile is almost always irresponsible. However, it is not the role of the engineer to sit on the seat of the manufacturer.
  • The naming of a production method is a means to indicate a desired shape, to classify. At the same time, the details of the production method are totally not interesting.

The engineer is not interested in the production method, but in the shape, function, price and features. So it's really weird that an engineer must appoint the production method. And that applies for the entire further chain too, purchasers, planners, project managers, all the way to the client. The reality is far from ideal and so the engineer is involuntarily confronted with a choice between warm-formed and cold-formed pipes, because there is a world of difference between the properties of the two.

Classification based on function

This approach is a lot better than the previous. Aluminium window and door profiles are an excellent example of such a classification by function. In fact, it is the only proper way to identify the twists of complex extrusion profiles. This is an important finding because it excludes other methods of classification. A drawing is the only guidance, and for a simple classification, function along with an index number referring to the standard, is the solution.

The function of a beam is also coupled to a shape. Here, however, the choice is limited so a number of core sizes of a basic shape meet. Interestingly, GOS works with numbers, European profiles often only have one distinctive number (HEA 180).

In structural steel, particularly I-sections, function is often intertwined with naming, such as "beam" and "column". However, structural steel such as L-forms can have numerous functions and can not be classified according to function. Back to I-sections. An engineer will choose what suits best. Perhaps there is a stock "columns" that can be used as "beam" or maybe the geometry of a "column" suits better than a "beam" in a given situation. A lot of beams are inclined or vertical while many columns are used horizontally. The name indicates the intention of use but is only moderately suitable for indexing a profile. The function as a classification can help but can also be confusing.

Altogether, classification based on function is unavoidable in many situations. When possible, classification based on shape is often preferred.

Classification based on shape

Classification on the basis of shape is parametric in nature. A solid round profile has only one parameter (diameter). The number of variants are innumerable, but in practice usually involves a limited number of standard sizes. A diameter of 8 mm is more common than 8.25 mm - probably nowhere on stock.

Using an I-section of type "W" or "IPE" will not cause any problems because the designation is sufficiently distinctive between the US and Europe. A different case are L-profiles. The same name is used all over the world but the shape differs in details per standard. In that case, the appropriate standard should be attached to indicate which family L-profiles is desired.

We'd like to leave that option open for CAD work. However, there is a strong temptation is to swipe all those similar shapes together and attach a region code label that can be used for its availability. That global region code may be a reference to a standard that is compatible.

It is at this point we felt the need to create a shape standard. You are welcome to adopt it.


This site is hosted by NedCAD.

De inhoud van deze site wordt aangeboden zoals het is, zonder enige vorm van garantie en heeft verschillende licenties. Meer informatie over licenties staat hier.