drafting

Types of Drawings in Projects

This article explains the 3 main types of drawings used in a projects for

  • Product development
  • Interior/ store design and development
  • Construction

Each type of drawings is referring to an entire stack created using the same software,

  • Concept Design Drawings (Hand sketches or 3D modeling using 3dsmax, Revit)
  • Technical Drawings (Autocad 2D and 3D, Inventor, Solidworks, Pro-E Revit)
  • Engineering Drawings (Inventor, Solidworks, Pro-E)

The above are 3 broad types of drawings which are used in different phases of a project. The concept design basically tries to produce a visual representation of the creative idea. The second step is to transfer the requirements into key specifications for manufacturers, however, it does not include all the details of “how to produce” yet. The final step is the use engineering drawings for manufacturing, which will break down into parts, and instructions for production, tolerance and assembly.

Confusion with Drawing Type

Recently we saw an article that there are 42 types of drawings, which can be quite confusing as they include “views” inside a drawing stack. This is just another internet blog trying to use bloated numbers to attract readers, which in the end may cause more confusion than value add.

For example,

  • “General Notes”, “Work Plan” etc are not a type of drawing. They are either tables or notes.
  • “Location Plan” is not a type of drawing per se. Basically we take site plan, scale it down, and place it at a corner of the detailed drawing so show which part of the site the detailing is located.
  • Drawing titles like “excavation plan”, “plinth beam layout”, “column layout” etc, are just names of specific details of a site drawing, which may or may not exist depending on a site design.

So in reality, the main drawing types are only the few type of drawings is different, depending on the type of project and its complexity.

The confusion with the terms and types of drawings are common especially when it involves participants from different country and background. The drawings are basically the same but they could be called differently.

Concept Design

The concept design is the first step in any development project, and is the result of presenting creative ideas visually on paper or 3D models. This is the Design Phase which involves primarily the designer and the Initiator (see below). However in complex projects, the designer may get manufacturing specialists to provide technical advise if a design is feasible for production. This is to avoid creating a design that is approved by Requestor, only to find out that it cannot be achieved in production at a later stage.

The Requestor

The concept design is initialized by the client or boss (herein we call this the “Initiator “). The creative designer needs to interview the Initiator to understand the intention, the boundaries of the project, location, usage, functionality, look and feel expectations, and any other special requirements. This shall form the design brief which is the explains the design intent of the project.

In some companies, the Initiator could be the Design Director or Creative Design Lead whose main job is to create new design ideas.

Delivering the Concept Design

After understanding the requirements, the creative designer will then prepare a document to communicate his proposed design concept. Normally they include the following:

  • Design brief (and intent).
  • References and guides. Such references may include images of items, material, places, and even people in the creative process.
  • Hand sketches and/or 3D models.
  • Key specifications and functions explained using sketches or diagrams (if any).
  • Finishing schedule which may include special material.

The design document is then submitted to the Initiator, internal stakeholders or his own boss for approval before proceeding to the next step.

3D models or Hand Sketches?

Ideally if time allows, it is recommended to use both methods to ensure the design is communicated correctly.

  • The creative designers should provide the first hand sketches of his idea, and then
  • Pass them a 3D modeling designer to create a 3D model of the design.

It depends on the complexity of the item. If it is a simple bench, then perhaps just a sketch will do. However, a complex design such as a sports car will most likely start with a sketch followed by 3D renders of the design.

What are the Options for 3D models?

In projects where 3D models can be used during the concept phase, they provide better visualization for the client. The following are the options:

  • 3D model, basic rendering with colors (Solidworks, Inventor)
  • 3D model, realistic rendering with material textures, lighting and scenes (3dsmax, Vray)

For projects with shorter lead time, it is recommended to use Solidworks or Inventor directly to design the 3D models. Once approved, the models can be passed on to the next phase to create the Technical Drawings with minimal time involved.

If 3dsmax is used, the technical drawing will need to be created from scratch most of the time.

Purpose of 3D models

The purpose of the 3D models are only for decision making purpose at the start. Once approved, it is used to communicate efficiently for the downstream work which may involved bids and tenders, quotation, technical design, and sourcing activities.

So the 3D model is not very detailed at this time, but it serves to spell out the the approved requirements clearly:

  • Overall size
  • Material and colors
  • Functions (if any), such as drawers, lighting, locks or even computer tablet holder, etc.

Normally, it does not include details of the section, components or assembly details at this time. However, those design created using Inventor or Solidworks may include such details built into the model. This could be due to reusing of 3D components (non-proprietary) from previous projects, e.g. a steering wheel, door handles, hinges, etc.

Advantages of 3D Models Over Sketches

The use of 3D textured models are better than hand sketches in design brief due to the following reasons:

  • It provides a more accurate look and feel, and drastically reduces the chance of miscommunication.
  • The 3D models can be modified indefinitely. If the client or boss request for several options of looks and view angle, it is much easier to do that in 3D models than hand sketching.
  • If they are done using Inventor or Solidworks, the workflow can be shortened significantly as they can be passed on directly to production stage.

Even though the advantages are clear, whether or not 3D models are used depends on the complexity, budget and time allocated to complete the project.

Technical Drawings

After the concept design is approved, the technical drawings will be created for quotation and prototyping where applicable. These drawings could be done by the designer himself, or they may engage a Project Management Company to produce such drawings. While 3D models may not be always be required in the concept stage, technical drawings are essential to kick start the prototyping and manufacturing processes.

Different countries, companies and industry call these drawings differently and the name may include:

  • Construction Drawings
  • Shop Drawings
  • Technical Documentation (aka TD)
  • Etc…

Technical drawings are mainly presented in 2D views, and typically excludes assembly, BOM, and detailed component drawings. However, these 2D views could also be generated from 3D models. Moreover, some designers may find it faster and more efficient to produce such drawings by 3D parametric modeling as compared to Autocad 2D.

Purpose of Technical Drawings

The purpose of these drawings are to convert the sketches or 3D models, into detailed drawings with dimensions, and sections to show the proposed construction method. They normally include the following:

  • Plan View, or Site Plan for interior/construction
  • Front View, or Front Elevation for interior/construction
  • Side View, or Side Elevation for interior/construction
  • Section View. This may further include Plan Section, Side or Front Section.

Although such drawings show the intended construction method, it may not be used directly for manufacturing yet as it a more detailed production drawing is required. At this stage, either the Initiator or the assigned Project Manager has to ensure that the Technical Drawings cover all the key specifications of the design intent.

Engineering Drawings (Production Drawings)

Engineering drawings are very detailed drawings used for manufacturing purposes, which includes all the parts and custom components details such as tolerance, hardness, etc. They are normally used for mass produced items in factories, and not for one-off building construction and interior projects. For one-off projects and small volume production, some factories employ experienced craftsman to manually work out the cutting list on paper, regardless if they are steel, wood, glass or plastic components.

For projects which may lead to repeated orders in larger volume, a more structured process is required which leads to very detailed engineering drawings, which includes assembly, BOM, and components drawings. Each component, down to the last pin, may have its own sheet of drawing with detailed size, tolerance, hardness, and finishing. The component drawings are each split out into their respective processes, e.g. some items may be for 3D printing, some may be sent to the acrylic supplier, while others are produced inhouse.

Such engineering drawings are normally provided by the manufacturers themselves. Depending on the project type, the drawings may or may not require approval by external parties. For construction and certain proprietary or complex products such as cars, computers or defense products, there may be detailed design reviews on the engineering design at the prototyping stage. Others such as interior design do leave it to the manufacturers to ensure that the engineering design is robust. For example, if a prototype table is unstable or shaky, the manufacturer has to rectify the design and provide a new prototype to show that it has been resolved.

After the final design is approved, the actual production and installation (if applicable) starts. Along the way, there might be variations and modifications which are quite common in construction and interior design projects. However such changes are less likely to happen in manufacturing as such changes would normally affect the cost. Even if they do happen, it is normally caused by an oversight during prototyping phase. Another example is unexpected reliability issue, which requires the component to be replaced by a new design.

Other Types of Drawings

The other types of drawings required may come after the final product or deliverable is completed. Some examples as below:

  • User manuals may require drawings related to operating, installation, maintenance, repair and replacement and safety, etc.
  • Product marketing material or website may require realistic 3D renders for presentation purposes, such as mobile phones, tablets, etc.
  • Construction projects will require the technical drawings to be updated to “As-Built” quality.