Presentation on theme: "Graphic Communication"— Presentation transcript:
1Graphic Communication Nairn AcademyGraphic CommunicationDepartmentofTechnologicalEducation
2Isometric Circle – 30o/60o generators method Department of Technological EducationIsometric Circle – 30o/60o generators methodStart the isometric circle by drawing the front elevation and the plan of the cylinder to be drawn.
3Locating Lowest Corner + Drawing Isometric Crate Department of Technological EducationLocating Lowest Corner + Drawing Isometric CrateChoose a suitable point ‘X’ on the elevation and plan and a suitable position to start the isometric view.xDraw an isometric crate to fit the isometric view into. Use 30o and vertical lines for the angles of the lines. The overall size of the crate should be the exact size of the isometric view to be drawn.xx
4Finding Centre for Isometric Circle Department of Technological EducationFinding Centre for Isometric CircleDraw centre lines on the isometric view. Use 30o and vertical lines for this.xx
5Finding Points on Circumference of Circle Department of Technological EducationFinding Points on Circumference of CircleDivide the orthographic circle into 12 equal parts using 30o and 60o lines generated out from the centre.x11211Number each of the points where the generators cut the circumference of the circle – usually done in the same format as a clock.29384756x
6Transferring Circumference Points to Isometric (1) Department of Technological EducationTransferring Circumference Points to Isometric (1)Project points where generator lines cut circumference of circle down and up to horizontal centre line of circle.x1121Measure horizontal sizes of projected points along centre line with compasses and transfer these sizes onto 30o isometric centre line.129384Project vertical lines through these points so that circumference points can be found.756x
7Transferring Circumference Points to Isometric (2) Department of Technological EducationTransferring Circumference Points to Isometric (2)Using compasses, measure the vertical distances from the centre line up and down to each of the points on the circumference in turn.Transfer each of these dimensions onto the isometric view.Number each of the points.x1298765431121192873645
8Drawing Isometric Curve Department of Technological EducationDrawing Isometric CurveDraw a smooth curve through each of the points to show the circumference of the isometric circle.x1298765431121192873645
9Determining Thickness of Cylinder Department of Technological EducationDetermining Thickness of CylinderTo show the thickness of the cylinder in the isometric view it is necessary to project each of the points found back at 30o.x129876543Measure the thickness of the cylinder on the plan using compasses and transfer these sizes onto the isometric. (In this case all of the sizes are the same but this may not always be the case).It is not necessary to transfer all of the dimensions as all of the points will not be seen at the end – however if in doubt it is better to transfer all and then only use the required ones.
10Drawing Back Curve of Cylinder Department of Technological EducationDrawing Back Curve of CylinderIt is necessary to find two final points – the tangent points - to indicate how far out past points 4 and 5 and points 10 and 11 that the curve passes.This can be done in two ways – by finding points A and B on the elevation and transferring these points to the isometric in the same way as points 1 to 12.x129876543AA– or by drawing diagonal lines on the isometric to find where the corresponding points occur on the front curve in the isometric.These points can then be projected back and measured as before to find the final positions.BBFinally, draw a smooth curve through each of the points found.
11Finishing Isometric View Department of Technological EducationFinishing Isometric ViewTo finish the drawing darken the required part of the outline of the curve.x129876543ABComplete the two edges to join the two curves together.
12The Final Drawing x This is the final Isometric View of the cylinder. Department of Technological EducationThe Final DrawingThis is the final Isometric View of the cylinder.x
13PowerPoint Presentation produced by John McRae, Nairn Academy 2003