Engineering Drawing Chapter-4 Solids.ppt
- 16. X Y STANDING ON H.P On it’s base. RESTING ON H.P On one point of base circle. LYING ON H.P On one generator. (Axis perpendicular to Hp And // to Vp.) (Axis inclined to Hp And // to Vp) (Axis inclined to Hp And // to Vp) While observing Fv, x-y line represents Horizontal Plane. (Hp) Axis perpendicular to Vp And // to Hp Axis inclined to Vp And // to Hp Axis inclined to Vp And // to Hp X Y F.V. F.V. F.V. T.V. T.V. T.V. While observing Tv, x-y line represents Vertical Plane. (Vp) STANDING ON V.P On it’s base. RESTING ON V.P On one point of base circle. LYING ON V.P On one generator.
- 17. STEPS TO SOLVE PROBLEMS IN SOLIDS Problem is solved in three steps: STEP 1: ASSUME SOLID STANDING ON THE PLANE WITH WHICH IT IS MAKING INCLINATION. ( IF IT IS INCLINED TO HP, ASSUME IT STANDING ON HP) ( IF IT IS INCLINED TO VP, ASSUME IT STANDING ON VP) IF STANDING ON HP - IT’S TV WILL BE TRUE SHAPE OF IT’S BASE OR TOP: IF STANDING ON VP - IT’S FV WILL BE TRUE SHAPE OF IT’S BASE OR TOP. BEGIN WITH THIS VIEW: IT’S OTHER VIEW WILL BE A RECTANGLE ( IF SOLID IS CYLINDER OR ONE OF THE PRISMS): IT’S OTHER VIEW WILL BE A TRIANGLE ( IF SOLID IS CONE OR ONE OF THE PYRAMIDS): DRAW FV & TV OF THAT SOLID IN STANDING POSITION: STEP 2: CONSIDERING SOLID’S INCLINATION ( AXIS POSITION ) DRAW IT’S FV & TV. STEP 3: IN LAST STEP, CONSIDERING REMAINING INCLINATION, DRAW IT’S FINAL FV & TV. AXIS VERTICAL AXIS INCLINED HP AXIS INCLINED VP AXIS VERTICAL AXIS INCLINED HP AXIS INCLINED VP AXIS TO VP er AXIS INCLINED VP AXIS INCLINED HP AXIS TO VP er AXIS INCLINED VP AXIS INCLINED HP GENERAL PATTERN ( THREE STEPS ) OF SOLUTION: GROUP B SOLID. CONE GROUPA SOLID. CYLINDER GROUP B SOLID. CONE GROUPA SOLID. CYLINDER Three steps If solid is inclined to Hp Three steps If solid is inclined to Hp Three steps If solid is inclined to Vp Three steps If solid is inclined to Vp
- 18. X Y a b c d o o’ d’ c’ b’ a’ o1 d1 b1 c1 a1 a’1 d’1 c’1 b’1 o’1 a1 (APEX NEARER TO V.P). (APEX AWAY FROM V.P.) Problem 1. A square pyramid, 40 mm base sides and axis 60 mm long, has a triangular face on the ground and the vertical plane containing the axis makes an angle of 450 with the VP. Draw its projections. Take apex nearer to VP Solution Steps : Triangular face on Hp , means it is lying on Hp: 1.Assume it standing on Hp. 2.It’s Tv will show True Shape of base( square) 3.Draw square of 40mm sides with one side vertical Tv & taking 50 mm axis project Fv. ( a triangle) 4.Name all points as shown in illustration. 5.Draw 2nd Fv in lying position I.e.o’c’d’ face on xy. And project it’s Tv. 6.Make visible lines dark and hidden dotted, as per the procedure. 7.Then construct remaining inclination with Vp ( Vp containing axis ic the center line of 2nd Tv.Make it 450 to xy as shown take apex near to xy, as it is nearer to Vp) & project final Fv. For dark and dotted lines 1.Draw proper outline of new view DARK. 2. Decide direction of an observer. 3. Select nearest point to observer and draw all lines starting from it-dark. 4. Select farthest point to observer and draw all lines (remaining)from it- dotted.
- 19. X Y a b d c 1 2 4 3 a’ b’ c’ d’ 1’ 2’ 3’ 4’ 450 4’ 3’ 2’ 1’ d’ c’ b’ a’ 350 a1 b1 c1 d1 1 2 3 4 Problem 2: A cylinder 40 mm diameter and 50 mm axis is resting on one point of a base circle on Vp while it’s axis makes 450 with Vp and Fv of the axis 350 with Hp. Draw projections.. Solution Steps: Resting on Vp on one point of base, means inclined to Vp: 1.Assume it standing on Vp 2.It’s Fv will show True Shape of base & top( circle ) 3.Draw 40mm dia. Circle as Fv & taking 50 mm axis project Tv. ( a Rectangle) 4.Name all points as shown in illustration. 5.Draw 2nd Tv making axis 450 to xy And project it’s Fv above xy. 6.Make visible lines dark and hidden dotted, as per the procedure. 7.Then construct remaining inclination with Hp ( Fv of axis I.e. center line of view to xy as shown) & project final Tv.
- 20. Y Problem 3:A tetrahedron of 50 mm long edges is resting on one edge on Hp while one triangular face containing this edge is vertical and 450 inclined to Vp. Draw projections. X T L a o b c b’ a’ c’ o’ a1 c1 o1 b1 900 450 c’1 a’1 o’1 b’1 IMPORTANT: Tetrahedron is a special type of triangular pyramid in which base sides & slant edges are equal in length. Solid of four faces. Like cube it is also described by One dimension only.. Axis length generally not given. Solution Steps As it is resting assume it standing on Hp. Begin with Tv , an equilateral triangle as side case as shown: First project base points of Fv on xy, name those & axis line. From a’ with TL of edge, 50 mm, cut on axis line & mark o’ (as axis is not known, o’ is finalized by slant edge length) Then complete Fv. In 2nd Fv make face o’b’c’ vertical as said in problem. And like all previous problems solve completely.
- 21. FREELY SUSPENDED SOLIDS: Positions of CG, on axis, from base, for different solids are shown below. H H/2 H/4 GROUP A SOLIDS ( Cylinder & Prisms) GROUP B SOLIDS ( Cone & Pyramids) CG CG
- 22. X Y a’ d’ e’ c’ b’ o’ a b c d e o g’ H/4 H LINE d’g’ VERTICAL a’b’ c’ d’ o” e’ g’ a1 b1 o1 e1 d1 c1 a” e” d” c” b” FOR SIDE VIEW Problem 4: A pentagonal pyramid 30 mm base sides & 60 mm long axis, is freely suspended from one corner of base so that a plane containing it’s axis remains parallel to Vp. Draw it’s three views. IMPORTANT: When a solid is freely suspended from a corner, then line joining point of contact & C.G. remains vertical. ( Here axis shows inclination with Hp.) So in all such cases, assume solid standing on Hp initially.) Solution Steps: In all suspended cases axis shows inclination with Hp. 1.Hence assuming it standing on Hp, drew Tv - a regular pentagon,corner case. 2.Project Fv & locate CG position on axis – ( ¼ H from base.) and name g’ and Join it with corner d’ 3.As 2nd Fv, redraw first keeping line g’d’ vertical. 4.As usual project corresponding Tv and then Side View looking from.
- 23. 1 400 Axis Tv Length Axis Tv Length Axis True Length Locus of Center 1 c’1 a’1 b’1 e’1 d’1 h’1 f’1 g’1 o’1 h a b c d e g f y X a’ b’ d’ e’ c’ g’ f’ h’ o’ 450 a1 h1 f1 e1 d1 c1 b1 g1 o1 1 Problem 5: A right circular cone, 40 mm base diameter and 60 mm long axis is resting on Hp on one point of base circle such that it’s axis makes 450 inclination with Hp and 400 inclination with Vp. Draw it’s projections. This case resembles to problem no.7 & 9 from projections of planes topic. In previous all cases 2nd inclination was done by a parameter not showing TL.Like Tv of axis is inclined to Vp etc. But here it is clearly said that the axis is 400 inclined to Vp. Means here TL inclination is expected. So the same construction done in those Problems is done here also. See carefully the final Tv and inclination taken there. So assuming it standing on HP begin as usual.
- 24. 450 F.V. T.V. Aux.F.V. X Y Problem 10: A triangular prism, 40 mm base side 60 mm axis is lying on Hp on one rectangular face with axis perpendicular to Vp. One square pyramid is leaning on it’s face centrally with axis // to vp. It’s base side is 30 mm & axis is 60 mm long resting on Hp on one edge of base.Draw FV & TV of both solids.Project another FV on an AVP 450 inclined to VP. Steps : Draw Fv of lying prism ( an equilateral Triangle) And Fv of a leaning pyramid. Project Tv of both solids. Draw x1y1 450 inclined to xy and project aux.Fv on it. Mark the distances of first FV from first xy for the distances of aux. Fv from x1y1 line. Note the observer’s directions Shown by arrows and further steps carefully.
- 25. X Y X1 Y1 AIP // to slant edge Showing true length i.e. a’- 1’ a’ b’ e’ c’ d’ 1’ 2’5’ 3’4’ Fv Tv Aux.Tv 1 2 3 4 5 a b d c e 1 2 3 4 5 b1 c1 d1 e1 a1 Problem 6: A frustum of regular hexagonal pyramid is standing on it’s larger base On Hp with one base side perpendicular to Vp.Draw it’s Fv & Tv. Project it’s Aux.Tv on an AIP parallel to one of the slant edges showing TL. Base side is 50 mm long , top side is 30 mm long and 50 mm is height of frustum.