autocad 3d how to draw on a specific surface

Basic 3D and Surface Modelling

Introduction

Although AutoCAD has a number of commands for creating special 3D objects, a lot tin exist achieved by changing the properties of bones 2D objects like polylines. Most 2D objects can exist given a thickness using the thickness choice in the Properties (DDCHPROP) command. Although objects with a thickness can be said to be extruded, this should not be confused with the EXTRUDE command which creates solid extrusions; giving an object thickness produces a surface extrusion. All objects can exist given an elevation by moving them in the Z direction using the Movement control. With a combination of the MOVE and Backdrop commands you can quickly create simple 3D drawings.

Using this tutorial you will learn how to give objects a thickness, how to move them vertically, how to view your 3D creations and how to use the 3DFACE and SHADE commands.

The DDVPOINT Command

You tin can utilise this command to get an axonometric view of your cartoon.

At that place are a number of ways to become an axonometric view of your AutoCAD drawing but the DDVPOINT command is probably the easiest and quickest to apply. It is, notwithstanding, cached two layers deep in the pull-down menu so it's oft quicker simply to type information technology at the keyboard, since at that place is no toolbar push. As you probably recognise from the command proper noun information technology is a dialogue box driven command. The Viewpoint Presets dialogue box is illustrated on the right. As you can see, yous define a view past specifying ii angles. The first angle is the rotation from the X axis (the horizontal bending). The second is the angle from the XY plane (the vertical angle). Using the dialogue box y'all can specify an angle either by picking on the two dials or by entering an angle into each of the 2 angle edit boxes. You lot can fifty-fifty await at your drawing from underneath by specifying a negative vertical angle. For most purposes a horizontal angle forth ane of the diagonals, 45, 135, 225 and 315 and a vertical angle of 30 give the best results.

You can render to a plan view of your cartoon by using the Plan command. To do this, just enter "PLAN" at the control prompt and and so to accept the "Current UCS" default. Yous tin as well return to any previous view by using the Zoom Previous command option, Z P at the keyboard or from the Standard toolbar.

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The Properties Control

Y'all can employ the DDCHPROP command to modify the colour, layer, linetype, linetype scale and thickness of any unmarried or multiple object selection. The DDMODIFY command gives all of these change options in addition to those which are specific to the object type. DDMODIFY is ever used past AutoCAD as a default for unmarried object selections when the Properties command is selected from the toolbar or from the pull-down menu.

Command Sequence

Command: DDCHPROP
Select objects: (pick one or more objects)
Select objects:
When y'all take selected the objects, the Change Properties dialogue box appears. To alter the thickness, simply enter a value (in drawing units) in the Thickness edit box. When you click the "OK" button your objects will be extruded by the amount specified.

The analogy (right) shows the result of applying a thickness to a circumvolve. A circumvolve with no thickness is shown on the left and a circle with thickness on the right.

Finer a circle with thickness becomes a cylinder. You can tell by the orientation of the UCS icon in this illustration that this is an axonometric view (see "The DDVPOINT Control" above for details).

Moving in the Z Direction

By now you should be quite used to using the Move command but upwards until now y'all've only been moving 2D objects in the XY Plane. Movement tin just equally hands be used to move a cartoon object vertically, perpendicular to the XY Plane. Y'all can exercise this by using XY and Z co-ordinates or by picking points in 3D space.

In the illustration on the left a circumvolve has been moved from the base plane of a cube to the top face of a cube. This is done by using the Motility command ( from the pull-downwards or from the Modify toolbar). Just get-go the Motion command, select the circle, pick i of the lower corners of the cube as the base of operations point (apply the stop signal Osnap!) and then choice the corresponding tiptop corner as the second bespeak, over again using the end point Osnap. If y'all expect at the circle in plan there appears to be no deviation in it's position considering information technology has non been moved in the XY plane only perpendicular to it. You can use the aforementioned principle to movement any drawing entity. Behave in mind that you must ever use an Osnap when you are picking points in 3D space. If you lot exercise not, the picked betoken will always be on the base plane, which doesn't make any sense. One of the problems with this is that y'all may non realise your mistake until y'all change your view position because in the current view the objects will appear to have been moved normally. It'due south a skilful idea to keep switching your view point as a check.

In the above case the move was fairly easy considering we had a cube to use as a guide. Very often you will need to motion an object vertically without any guide. In such a case you should use co-ordinates. For example, if the cube in the illustration higher up was xl drawing units loftier so I could move the circle using the following command sequence.

Command Sequence

Control: Motion
Select objects: (select the circle)
Select objects:
Base of operations point or displacement: 0,0,0
2nd point of displacement: 0,0,40

Notice that I utilize the UCS origin bespeak as a base signal, that's because it'due south standard do simply in principle it could be whatever point in space. The about of import thing is that the X and Y co-ordinates remain the same (because nosotros practise non want to move in the XY Airplane) and the Z co-ordinate must increase by the distance you want to move upwardly. Using according 25,43,xvi as the base betoken and 25,43,56 equally the second betoken would have resulted in exactly the same motion. To movement down you just need to specify a negative Z co-ordinate. For example to move the circle down by 40 units the second point according would be 0,0,-40.

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The 3D Face Control

The 3D Face command is used to depict 3D surfaces with 3 or iv edges.

Command Sequence

Command: 3DFACE
Starting time Point: (pick point)
Second Betoken: (choice point)
Third Point: (choice point)
Fourth Signal: (pick point or for just 3 edges)
Third Point: (start some other 3D Face or to cease)

Why practise I need a 3D Face?

The reason is that when you give an entity like a rectangle a thickness information technology is given solid sides in the direction of the extrusion but it is left open ended like a tube. To add a peak and a bottom to a box you lot must use 3D Faces. In the illustration on the right, ii boxes take been shaded using the Shade command, SHADE from the keyboard, from the pull-down or from the Render toolbar. Encounter SHADE for a description of the Shade command options. The box on the correct is a rectangle which has been given a thickness. As you lot can see, information technology does not accept a superlative. A 3D Face has been added to the top of the box on the left which gives the effect of a solid surface when shaded.

When you use the Shade control, don't forget to utilise the Regen command to get back to the wireline cartoon. AutoCAD does not allow you lot to option points on a shaded drawing.

For complicated shapes you may need to use a number of 3D Faces to fill a surface. Fortunately, extruded circles are automatically given a solid peak and lesser so y'all don't need whatever 3D Faces. If you do need to utilize a complex of faces to fill up a surface in that location is a manner to hide the join lines between faces. If you type "I" and earlier the first pick point of any edge, that edge volition exist made invisible. If you are careful you can easily fill a complicated surface with many 3D Faces which will simply appear as a single continuous surface. If y'all need to create a very circuitous surface information technology may be better to use the EXTRUDE command which creates solid extrusions i.e. they already take top and bottom surfaces.

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An Practice

The exercise below is designed so that y'all can practice all of the new commands and techniques outlined in a higher place. It is a simple table which is composed of nine primary elements, 4 legs, iv rails, and a top. These elements are all synthetic using the Rectangle command, RECTANG from the keyboard or from the pull-downward menu. Think, there is null special about rectangles, they are just four sided airtight polylines, and then if you prefer using the PLINE command, then feel gratuitous.

These rectangles volition be given a thickness using the Properties control and an elevation using the Motility command. Some 3D Faces are used for the finishing touches using the 3DFACE control.

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Drawing the Table

Step 1

Beginning of all draw the tabular array plan using the dimensions on the analogy and inset detail below. All dimensions are in millimetres. The plan is composed of nine rectangles. You lot may need to use other commands similar Line and Offset to construct the rectangles. Alternatively you tin can work out the rectangle co-ordinates and construct them manually. Remember to use the Copy and/or Mirror commands to duplicate identical objects. For example, information technology'due south actually only necessary to draw one leg since they are withal.

Step 2

Adjacent, using the Properties command, select the 4 tabular array legs and give them a thickness of 700. Using the Backdrop command a second time, select the 4 tabular array rails and requite them a thickness of 100. Motility the rails vertically through 600 with the Motility command using a co-ordinate value of 0,0,0 for the base point and 0,0,600 for the second point. Finally utilize the Properties control a third time to give the tabular array top a thickness of forty and utilize MOVE again to give the top an summit of 700. At present look at what you have created using the DDVPOINT command, from the pull-down or DDVPOINT at the keyboard. Use the SHADE command to see the solid event, from the pull-down or SHADE at the keyboard.

Step 3

As you volition have noticed, your table does non yet have a solid top. Y'all can achieve this using 3D Confront. You can start the 3D Face command from the pull-down, , from the Render toolbar, or from the keyboard, 3DFACE. 3D Faces are defined by picking the four points of a rectangle in either a clockwise or anticlockwise direction. Start the 3D Confront command and using the endpoint Osnap, select the iv upper corners of the tabular array top. Employ the Shade control again to come across the effect. You lot tin use more 3D Faces to complete the model. Past looking at the table from various angles you will find that the underside of the rail, the underside of the legs and the underside of the tabular array height all need 3D Faces in order to create a completely solid model.

At present that yous have completed your model, experiment with the Shade command and the various shade edge settings (see "Tips and Tricks" below).

Pace 4

To finish your drawing, set tilemode to 0, create an A3 cartoon sheet and insert some tiled viewports, see thePaper Space exercise for details. Your drawing should cease upwards looking something similar the one beneath. The vase was created using the REVSURF command, see REVSURF for details.

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3D Objects

In add-on to the elementary 3D objects yous can create past giving objects thickness and adding 3D Faces, AutoCAD provides a number of gear up fabricated 3D objects. These objects tin be chosen from the 3D Objects dialogue box. As you lot can run into from the illustration of the dialogue box below, yous can create very simple objects like a box and circuitous ones similar the torus.

You must invoke the 3D objects dialogue box from the pull-down menu, equally there is no keyboard equivalent. Alternatively you tin can select private 3D Object commands from the Surfaces toolbar. Each 3D Object requires different input from the user but the command line is quite explicit so you shouldn't have any problems.

One of the most useful objects is the Sphere. In the illustration on the correct a 3D tree has been created using a circumvolve with thickness as the trunk and a sphere equally the canopy. One thing to bear in mind when creating spheres is that the eye of the sphere will exist on the basis plane. Therefore, one-half of the sphere is beneath ground level and one-half higher up. If you want the sphere to sit down on the ground aeroplane, all you lot accept to do is move it up through a altitude which is the same as information technology's radius.

Another consideration when creating spheres and some of the other shapes is the number of segments to employ. It is very tempting to use a lot and create a smoothen shape just this does take lots of drawing memory so become carefully. The default value (16) is usually acceptable for nearly purposes.

Command Sequence

Invoke the dialogue box from the pull-down (), selection the sphere icon and so the "OK" push or pick from the Surfaces toolbar.

Heart of sphere: (pick point)
Diameter/<radius>: (pick point or enter value)
Number of longitudinal segments<16>: (enter number or)
Number of latitudinal segments<sixteen>: (enter number or)
Your Sphere is drawn.

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Tips & Tricks

• If you would like to try creating the vase every bit shown in the table drawing. You will need to know a little scrap about UCS, User Co-ordinate Systems (run across UCS) and how the Revolved Surface control works (come across the 3D Tree do for details).
• You can change the shaded consequence that the Shade command gives to your cartoon using the SHADEDGE variable. To change the shade border variable simply enter SHADEDGE at the keyboard and enter a value between 0 and 3.
  SHADEDGE = 0 gives a shaded colour surface with no lines.
  SHADEDGE = 1 gives a shaded colour surface with lines. This tends to give the best overall results.
  SHADEDGE = 2 gives a background colour surface which gives a similar result to the Hibernate command.
  SHADEDGE = 3 gives a block colour surface, this is the AutoCAD default. See SHADE for a fuller description of the SHADEDGE variable.
• Always use Osnaps when picking in 3D.
• Use the Shade control regularly to keep track of your drawing. In wireline it's impossible to tell if a surface has a 3D Face up or not, so you'll need to utilise Shade to check.
• You tin strength invisible 3D Confront edges to display in wireline using the SPLFRAME variable. If SPLFRAME = 0 all invisible edges remain hidden. If information technology is set to one invisible edges volition be displayed. This tin be extremely useful considering information technology is impossible to select a 3D Face which has no visible edges. The only style to select such a 3D Face is to set SPLFRAME to 1 first.

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