AutoCAD orthographic Drawings:
AutoCAD Orthographic drawings provide the two-dimensional views of plant 3D models of engineering components, piping systems, valves, machine equipment’s and structural steel. The drawings may be annotated, measured and matched and display or conceal lines and objects.
Steps in drawing AutoCAD orthographic views from pictorial views:
1. Study the given pictorial sketch or object carefully following the principles of orthographic projection
2. Prepare sketches of the required orthographic views from the picture or object or model before scale drawing is started
3. Make a preliminary measuring and determine the space required for the chosen combination of views
4. Select a suitable scale if necessary
5. Space the views and block out the spaces for the views
6. Draw centre lines of symmetrical parts like cylinder and centres of circles if visible
7. Build up the details in each view starting with the most characteristics shape and then proceeding to minor details. Carry the views along together and do not attempt to finish one view before taking up another. Keep the construction lines minimum and draw the lines to finished thickness, if possible.
Note: it is not possible to draw the top and side views directly. The depth measurements are relocated from one point to the other point. Mitre lines is sometimes used to transfer the measurements. Mitre line is a 45 degree line drawn through the points of intersection of the top and side views of the front edge. Use of a mitre line is not recommended since it takes more time and requires great care.
8. Check whether all the hidden features are shown in the drawing by dashed lines
9. Erase the extra construction lines after drawing the required views
10. Complete the dimensioning including the titles and notes
11. Check the drawing for accuracy and ascertain that it is complete in all respects.
What are the four orthographic views?
An orthographic projection is a method of depicting a three-dimensional object by combining numerous two-dimensional views of the component. Multi views are another name for orthographic drawings. The top, front, and right side views have been the most frequent. Those three points of view are projected and aligned with each other.
Different reference planes to draw the AutoCAD orthographic projection are:
- Horizontal plane
- Vertical plane
- Side plane or profile plane
Different orthographic views to mention the Autocad orthographic projection are:
- Front view (Projected on vertical plane (VP))
- Top view (Projected on horizontal plane (HP))
- Side view (Projected on Side plane (PP))
Types of Projections:
- Parallel projection
- Axonometric views or pictorial drawing (30° angle inclination to draw isometric drawings)
- Pictorial drawing (0° angle inclination to draw isometric drawings)
- Perspective projection
- Perspective drawing
What is an AutoCAD isometric drawing?
An isometric AutoCAD drawing is a 2 dimensional drawing is like a paper drawing. AutoCAD has certain tools, but not too many, that help us create the drawing. We will mostly utilise the same commands we used during orthographic drawings.
What is the difference between orthographic and isometric projection?
Isometric projection: The way by which three planes of a component are shown, portraying three-dimensional objects on the flat surface.
Orthographic projection: A three-dimensional object representation approach via multiple views on different 2D reference planes.
What is the difference between a first-angle and a third-angle projection?
A component’s view is drawn adjacent to where it was captured in third-angle projection. The view is drawn on the opposite end of the component from where the view was captured in first-angle projection.
First angle projection is a ISO standard system and it is followed by european countries, whereas Third angle projection is followed by India, Canada, USA, Japan and many other countries.
What are the benefits of using an orthographic drawing?
The advantages of AutoCAD orthographic projections are: hidden details and connection components are shown. You can display all the essential measurements for production. The material and finishes can be annotated.