Gallery - Watch

This model was amongst my first few models when I was learning CAD modeling. Was done using SolidWorks, All the components are  created by Extrude and Revolve function only.

The biggest challenge of this model is that the chain that is not exactly flat, but at some certain radius. Nevertheless, it could be done using a simple revolve cut.

If you are interested to download the raw files, you can download it here.

The hook - not that easy to model a fully functioning hook

Overall Assembly

One of the most difficult section to model back then.

The other end

Back-side of the chain

SolidWorks - Revolve

Same like the extrude function, the revolve function is also divided into two category, the Revolved Boss/Base and Cut-Revolve. To understand the basic operation of revolve function and the difference between boss and cut, refer here.

Accessing the Function
Similar like the extrude function, you could access the revolve function from the ribbon.

Alternatively, you can go to Insert > Boss/Base > Revolve for Revolved Boss/Base. For Revolved Cut, you can click Insert > Cut > Revolve.

Revolved Options

Just like Extrude function, the Revolve function also has few options. The interface of the function is shown in picture below.

Revolve Type

Under Revolve-Type option, there are few options could be chosen, which are Blind, Up To Vertex, Up To Surface, Offset From Surface, and Mid Plane. By default, it is set to Blind. All these options has its own advantages, depending on its application.

Thin Feature

Just like Extrude, you can also have Thin Feature option on Revolve. The Thin-Feature option would create an offset to the selected profile. The offset distance is determined by the user. Thin-feature is extremely useful for doing a piping modeling.

The effect of Thin-Feature is seen in figure below, where a revolve angle of 270 degree, Thin-Feature with offset distance of 5 mm is determined by the user. The result would be a 3/4 revolution of hollow pipe.

Selected Contours

When there are more than one closed loop contours, user can choose which contours they wish to revolve. This works the same way as Selected Contours in Extrude function.

SolidWorks - Extrude

There are two types of extrude in SolidWorks, Boss-extrude and Cut-Extrude. The main difference between these two is that Boss-extrude is used to add material, and Cut-Extrude is to remove material (read more about add and remove material here).

Accessing the Function

The easiest way to access these two functions is through the icon on the ribbon.

Alternatively, these functions could be accessed by clicking Insert > Boss/Base > Extrude for Boss-Extrude or Insert > Cut > Extrude for Cut-Extrude.

Extrusion Options

Opening up the menu, there are few features that you can play with. 

Starting Condition

The starting condition defines where the extrusion would start. By default, it would be from the sketching plane. However, you could select other options such as from specified surface, or by defining an offset distance from the sketch plane.

Starting Condition Options

End Condition

The end condition options allow you to determine how you are going to terminate the extrusion feature. The default is on blind, where you specify the depth of the extrusion. You could use a surface to specify the depth of the extrusion in the event where the desired depth is not known.

End Condition Options

Draft Angle

The draft-angle option allow you to create a draft angle along the extrusion instead of having it perpendicular to the sketching plane. For example, applying draft angle on a circular sketch would result in a conical shape as shown below.

Draft Angle Option

Thin-Feature

The thin-feature function allow you to create a hollow solid with certain wall thickness.

Thin-feature option 

You can have cap-ends function as well to have the center section to be end-capped. The thickness of the cap is user defined.

Effect of having end-caps option

Selecting Contours

In the event where there are more than one closed-loop region in the sketch, you could select which region you want to extrude using the selected-contours option. For illustration, there are four closed loop region shown in figure below, and two are selected to be extruded.

Selected Contours option

This operation would result a solid which looks like this:

Resulted Solid

SolidWorks - Orienting the View

In all CAD software, there are three most fundamental view orientation could be done: pan, rotate, and zoom. In each software, how to navigate the view can varies. Here is how you can navigate your view in SolidWorks.

Pan

To pan the view, you need to hold down the ctrl key and the mouse scroll button while moving your mouse to the direction you want to move.

Rotate

Rotate view can be achieved simply by holding the mouse scroll button, and move your mouse to the direction you want to rotate. Rotation could be achieved by using the arrow keys as well.

Zoom

To zoom view, you could scroll up your mouse to zoom out, and scroll down to zoom in the view. There are another method that you could use using the button in view setting region.

   Zoom to fit - clicking on this icon would zoom the model to fit the window.

   Zoom to area - to zoom in to an area that you select. Clicking this icon would prompt you to select the area which you want to zoom in.

   Previous view - to display the previous view state.

Other than using this options, SolidWorks also have very useful tool to orientate the view accurately. The orientation menu could be trigerred by pressing space bar. 

On the orientation menu, there are view options you could choose by double-clicking on the view name. For example if you select front, SolidWorks would automatically orientate the view such that user would view the front of the model. To use the *Nomal To view, a surface should be selected in advance.

You could also save certain view that you want by clicking on the New View icon.

SolidWorks - User Interface

For basic operation, new user should be familiar with the most basic SolidWorks interfaces. The basic interface of Solidworks is shown below:

- Workspace

Workspace is where your 3D model is displayed.

- Function tree

Function tree contains all your building features in order from the earliest on top, to the latest below. For assembly, the function tree contains all the parts that form the assembly.

The topmost of the function tree is always occupied by default features such as the top, front, and right plane; and origin.

- Ribbon

Ribbon contains the shortcuts to the most commonly used functions. The ribbon itself contains few tabs such as features, sketch, evaluate, etc. User could customize what tab they want in the ribbon.

- View Setting

The view setting contains some options regarding the view of the model. Some options that could be chosen such as section view, view orientation, view display, background scene, zoom, etc.

- Library

The library contains some pre-defined function of standard components such as bolt, nut, washer, and others.

- Customizable toolbar

If you feel that the ribbon is not enough to contain all the shortcut you want to use, you can customize your own toolbar. In the picture shown, I am putting selection filter in the toolbar.

CAD Files

In general, there are three types of basic CAD files, they are:

1. Part

Part is the most basic entity of the CAD files. Part is a representation of a single design component and most of the time is the building block of a bigger system.

2. Assembly

Assembly is a combination of parts or another assemblies to form the whole system. An assembly inside an assembly is commonly called as sub-assembly.

3. Drawing

Drawing is a 2D drawing consisting details of either part or assembly. Drawing of a part usually consists of the dimension of the part, how to fabricate the part, etcc. Drawing of an assembly usually contain the information how to assembly the whole system.

To give an illustration of this structure, imagine of  a simple pen like below.

The pen itself is an assembly, consisting some parts namely the cap, outer tube, end cap, rubber handle, and the refill. The refill is an sub assembly in this case as the refill consists of the tip, the refill tube, and ink.

There are, however, some CAD system that has more than three types of CAD files as mentioned above. For example, Autodesk Inventor has Presentation type file, which can is mainly to create a "display" of an assembly, for example exploded view. These additional CAD files are just extra, and create some unique selling point for each CAD software. But on principal, all CAD software would have the three basic CAD files as mentioned above. Part, Assembly, and Drawing.

Basic of 3D modeling (2)

As I promised from my previous post, I am going to post the basic of 3D object creation for solid base modeling. This post should serve as general guidelines for all CAD software as their basic principles are the same. There's only slight difference in terms of the interface and options.

To start with, let me tell you the basic operation of 3D solid base modeling. All the 3D objects are created from 2D sketch. Then this 2D sketch is being manipulated by 3D feature to create 3D object.

Creating 2D sketch

To begin with, you need to create a 2D sketch. The sketch must be sketched on a sketching plane. All CAD software would have 3 default sketching plane, the Top Plane, Front Plane, and Right Plane. It is recommended to create the first sketch on either one of this sketch. In future, additional plane could be created if it is necessary.

Default initial sketching plane

After the sketch is created, you could start making the 3D model using the features. Here is the basic features that all is widely used by all 3D CAD software available.

Extrude

The basic of extrude feature is to "pull" the 2D sketch to direction perpendicular of the sketch. See image below for clearer illustration. Other options such as draft angle varies according to different CAD software.

Basic of extrude feature

Revolve

The basic of revolve feature is to create a closed loop 2D sketch and an axis of revolution. The solid model would be radially symmetric to its axis of revolution. See image below for clearer illustration.

Basic of revolve feature

Extrude and revolve are two of the most basic feature to create a solid as it can be created using sketch that lies on the same plane. The subsequent feature require more than 1 sketch that must lie on a different sketching plane.

Sweep

To do sweep operation, you need to have a closed loop 2D sketch (referred as the profile) and a sweeping path (referred as the path) that does not lie on the same sketching plane as the sweep profile. Whether or not  the path should intersect with the profile varies widely according to different software. Refer to image below for better illustration.

Basic of sweep feature

Loft

To make a lofted profile, you need to have at least 2 close loop sketches. The loft function then would fit in a solid that passes through/fit the profile. To understand better, see the image below. We see that loft function would fit a profile that changes gradually from a rectangle into a circle.

Basic of loft feature

To form a complex model, we can not use only one feature. We need to use multiple features one after another. Generally, all the feature above could be used to form solid, or to remove them. All the used features then would be stacked one after another on the model tree.

Add material

To understand how we build feature after another, imagine if we have a cube as shown below after doing an extrude feature.

We then can draw a circle on the top face of the cube.

We then could do extrude feature on the circle to form a solid as shown below:

Cut material

Now imagine we have the same cube as shown above. Instead of adding a cylinder on top of it, I could select extrude cut which would remove material in shape of cylinder, instead of adding material on top of it. As a result, you would get something like this:

And that is what I mean by stacking feature after feature. In this case, only 2 features are being used. In a complex model, up to 30 feature is quite a common thing.

And now you have understood the basic operations, and literally, you now you could start building your own 3D model!

Basic of 3D Modelling (1)

For those who are not so familiar with 3D modeling, they often wonder how to create a 3D objects. Before going into detail how to create 3D models, first we need to know about CAD software systems that currently exist.

Currently, there are 2 types of CAD software system that exist; Solid base and surface base. Example of soled base software are AutoCAD, Autodesk Inventor, SolidWorks, Solid Edges, Pro/Engineer, etc. Few names for the surface based software are Rhino, Autodesk Alias, etc. Most of the software, though I listed as solid base, are capable of doing surface based modeling as well, just not as convenient as naturally surface based software. The other way round is also applicable to surface based software.

So comes to the point, what is the difference between solid base modeling and surface based modeling?

As the name suggest, solid base modeling produce a solid model. The term solid means that it is not hollow. When you do an imaginary cut over the model, everything is filled up by the material. On the other hand, surface based modeling produced a very thin surface that outline the shape of the model. When you do an imaginary cut over the model, inside it would be empty.

 Two boxes, done by solid modeling (left) and surface modeling (right)

After doing a section cut on the plane shown, the difference could be seen.

Alright, now comes to the important part.

Which one is better, solid base or surface base software?

The answer pretty much depends on your application. In general, solid base modeling is better to be used for more regular-shape and well defined object. For example in machine design where the actual product would be solid. Surface based modeling suits for product with more irregular and advance shape that is often used by the product design engineer or in automotive industry. Example of surface base modeling is to model a computer mouse. It has rather complex surface compared to machine linkages.

Of course this is just a rule of thumb and should not be taken as absolute measure. There is no superiority between these two systems, it all depends on the application. Flight hour of the user is also important to be able to determine which CAD system suits them best.

Which one is easier to learn, solid base of surface base software?

Well, difficulties is a rather subjective matter, but to me, solid base software is much easier to learn. First it is more user friendly (for most of the software at least). Second, the way it works, is easier to imagine as it works from 2D sketch and turn it into 3D model. At least no 3D sketch is involved unless the model is really complex.

On the next post, I'm going to post the basic of creating models on solid base system on most of the software.

What is CAD?

CAD stands for Computer Aided Design. It is basically using computer technology to help people doing design. The design could range from mechanical and machinery industry, product design, up to architectural design.

CAD software was first introduced on 1980s, where computer started to advance. It quickly replaces hand-design which has a lot of drawbacks and is very messy. CAD software improves the efficiency of design process significantly. At this age, almost all designs is done through CAD as computing cost has decreased significantly over the past ten years.

While a lot people think that CAD is referring to 3D modelling, CAD actually refers to both 2D and 3D design. For most cases, 3D modelling is preferred compared to 2D design as 2D design requires higher skills to analyze the design. However, 2D design is still more favorable on some applications. For example, drawing schematic layout and diagrams.

Below is some screenshots of CAD modelling, both 2D and 3D designs ranging from very simple design until  more complex modelling.

* Images courtesy of CAD-for-Dummies.blogspot.com. All the CAD files shown below are hardworks of the writer. Do not use any of the images without acknowledging the source *

Compass designed in SolidWorks

Watch designed in SolidWorks

Extension plug designed in Autodesk Inventor

My old phone, Motorola Milestone in SolidWorks

Small design done in AutoCAD

 Model of Nissan 350Z in SolidWorks

Range Rover Classic in SolidWorks

Looking at all the pictures above, do you feel like learning CAD modelling? Afraid not as CAD modelling is not difficult. In the following post I'm going to post the basic of CAD modelling and some "Tips and Tricks".

First!

Well, just like on other comments on other websites, there has always been people who post: "First!".

This would "First!"post would mark the beginning of this blog.

CAD for Dummies.

In this blog, I would post various trick and tips to CAD modelling. Hopefully I would keep this blog going. So please support me :D

Thank you for viewing, hope it would help you :)