Landscape CAD Standard

It is important that your CAD drawings are structured in a consistent and organised manner. Here we will attempt to define a CAD standard for landscapers using software such as GardenCAD. The standard set our below is a work in progress and is designed to help you produce drawings which conform to the spirit of the Australian Standard for Technical Drafting - AS1100 and its sub-parts. We want you to create your own version of this standard.

This document

The CAD standards manual is should be a controlled document and exist as part of your quality system. You should use a proper word processor such as Microsoft Word to create the document and include the author's name, date, revision status etc. in appropriate headers and footers in the document. The in-built word processor available to Windows users as part of the operating system (WordPad) is not a suitable software tool.

If you do not know how to create footers and headers and date and timestamp, then take on online course on the use of MS Word (see http://www.softwaretutor.net).

Here is a list of sections to include in your CAD standards document.

1. Contents

Your manual should have an accurate table of contents and an index, just like the GardenCAD user guide. This makes it more likely that the manual will actually be used. If you use named styles, you can make the generation of a table of contents in your CAD standards manual an automatic task.

2. Introduction

Your manual should have some sort of general introduction indicating the reason for producing the document and why people should be following it. E.g. ‘This document describes Computer Aided Design (CAD) procedures to be adopted on projects at ACME Landscape Designers (‘the company’). It is to be used internally as an office standard and issued to outside consultants. The aim is to provide a sound basis for the production of electronic drawings’.

3. CAD software

Clearly, we use GardenCAD, but since GardenCAD is compatible with AutoCAD and IntelliCAD, the CAD standards approach would be the similar no matter which CAD software you use.

4. Staff responsibilities

The responsibilities of staff and contractors need to be made very clear. To whom does this standard apply? For example, ‘this procedure applies to any staff member of a design group preparing CAD drawings in any discipline and to outside contract organizations delivering CAD drawings to ACME Landscape Designers.

5. References, standards etc.

It is most useful to include a comprehensive list of all the standards that you expect drafters to use in the production of their work. AS1100 - the Australian Standard for Technical Drfating has most relevance here.

6. Step by step procedures for CAD

After discussing general issues, we have found that the most effective way to help a reader come to grips with what the company is aiming for, is to take them metaphorically though the creation of a CAD drawing using the CAD software of choice. This helps even very experienced drafters ‘come to grips’ with the way in which the company produces CAD drawings. Experienced workers have often become very set in their ways of working and need some gentle coercing to move to a slightly different way of doing things. It is really helpful if you include diagrams (screen grabs) in your document wherever possible to illustrate the steps involved.

6.1 Starting a new drawing

How do you start the CAD program? Do you expect the CAD designer to use a particular template? What configuration variables need to be set before beginning? The GardenCAD web site has copies of drawings of title blocks with attributes. Are these going to be used?

6.2 Drawing sheets

How is layering organised in the title block? One standard we are aware of includes the note that attributes for parameters such as checked have not been set as the company prefers a signature rather than CAD text to indicate acceptance of a design. The figure below shows an example of part of the title block area of an A1 sheet.

Among other data, the following should be included in the title block:

• Name and address of the design authority (the designer) whose code identification and drawing number appear in the title block.
• Drawing title
• Drawing Number
• Record of information relative to the preparation of the drawing including drafter name, checkers name, approving function contractor's name and reference number if applicable
• Drawing sheet size designation
• Predominant scale of the drawing

Give some indication as to sheet sizes to be used. Such as, ‘As a general rule, the company requires drawings on A1 sheets. However, for field use we also require our A1 drawings to be plotted on A3 sheets, changing scale automatically. The figure below shows a special scale block used for this purpose.

Comments need to be made regarding naming systems. For simple projects that do not contain multiple zones in multiple drawings, file naming is to be in the following format. A 123 PL 01 .DWG or DGN where A represents the discipline – A for architecture, L for landscape, P for planning, D for interior design, M for marketing etc. the 123 represents the project number, the PL represents the file description – PL for plans, EL for elevations, SE for sections, SI for site plans etc while the final two characters are for multiple occurrences of similar file descriptions. 01 is always the first file.

6.3 Sizes, units, spaces and scales

The use of units and sub-units needs to be carefully defined. A statement thus ‘Drawing units are taken as mm. All objects are to be drawn full size in model space. Adopting this strategy means that any enquiry in model space (listing properties of an entity in GardenCAD or use of the DISTANCE command) can be made of any drawing and true distances (in mm) will be reported. To reiterate, all objects are drawn actual size, do not draw in the sheet files.’

6.4 Use of colour

Colour can be controlled by level or set implicitly or even a combination of the two. Confusion reigns if this issue is not dealt with clearly. A GardenCAD specification might state ‘The use of colour in CAD drawings will conform to the ISO colour system, which is loosely based on the Rotring pen colour coding system commonly used in manual drafting. The following colours are to be used.

6.5 Layers

The American Institute of Architects have published a standard for layer names in CAD drawings. All layers containing landscape information should begin with the prefix L-. Hence an irrigation layer will be called L-IRRIG, a layer for a landscape construction team L-CONSTRUCTION, a layer for a plant symbol L-PLNT [hence L-PLNT-SYMBOL for a layer containing the 'fancy' decoration of a plant symbol in GardenCAD] and so on. We also use the following layers - L-BOUNDARIES, L-SERVICES,

6.6 Text

A font closely matching ISO3098B font will be used for all lettering with heights of text inside drawing sheets as per AS1100 (AS1100.101 -1992, Section 4 1.5). The styles Romand (with font Romand) and Romans (with font Romans) are used in title block information, but are not to be used inside the sheet. In AutoCAD, the style ISO3098B is defined as follows:

Final text height (h) sizes will be 2.5, 3.5, 5.0, 7.0, 10, 14 and 20 mm as required by AS1100 (4 2).  The minimum height of text is controlled for ensuring clarity. On A0 sheets minimum text height is to be 3.5 mm in general notes, materials lists and dimensions. We also prefer 3.5 mm as the minimum height for these elements in the A1 to A4 sheet series.

6.7 Dimensioning

Comment and guidance is needed for dimensioning. Eg ‘Dimensioning should normally be expressed as mm. Dimensions of less than unity should be preceded by zero eg. 0.6 mm. Each dimension should appear only once and not repeated in other views. Dimensions should be placed outside the component if possible. Dimension text should also be placed so that it may be read from bottom or right-hand side of the drawing. Figure 6 shows a part dimensioned to the company style.

7. Examples from parts of acceptable landscape drawings

Legend

Plant schedule

Typical plan