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AutoCAD 2015 and AutoCAD LT 2015 Bible

The most comprehensive AutoCAD book around!

Creating models for 3D printing

AutoCAD can export to STL format which is what some 3D printers use.

Choose File (the Application button), Export, Other Formats and choose Lithography (*.stl) from the Files of Type drp-down list. Then select the objects that you want to include. There’s also an option Application button, Publish, Send to 3D Print Service.


from http://www.3dartistonline.com/news/2011/12/how-to-make-a-model-for-3d-printing/

With a 3D printer, we can create objects impossible to make as a single piece by other means of production. It is possible to print objects within objects, hollow parts, interconnected parts, moving pieces, complex twists, and intricate details.

There are numerous 3D printing technologies out there; stereolithography (SLA), selective laser sintering (SLS) and fuse depositing modelling (FDM) to name but a few, and each has pros and cons.

When you are considering preparing a piece for 3D printing – in this example, we’ll be producing an object in ceramics – we must first consider the design constraints before we select the 3D printing process.

In the case of ceramics, the minimum wall thickness possible is 3mm; the maximum detail is 2mm. In other processes, such as SLS, the minimum wall thickness might be as thin as 0.7mm and the minimum detail as sharp as 0.2mm, so it’s very important to know the process.

Something else to consider is cost – 3D printing is not necessarily a cheap process, so try to use as little material as possible.

Step 1 – Modelling

You can pretty much 3D print everything from organic ZBrush sculptures, mathematically complex models and sleek product designs, to your computer game avatar. Whatever you’re designing, keep in mind the real world. Your 3D model will become an actual object, so you must consider dimensions, strength and gravity.

So, for example, if you want to 3D print a figurine, make sure it will stand on its own two (or however many) feet, or consider adding a base.

from http://www.3ders.org/3d-printing-basics.html#3d-software-for-beginners

If you’re just getting started you can try some of 3D modeling software which can be downloaded for free.

  • Google SketchUp – This Google SketchUp is fun and free, and is known for being easy to use. To build models in SketchUp, you draw edges and faces using a few simple tools that you can learn in a short time. With with Push/Pull tool you can extrude any flat surface into a 3D form. Furthermore, it works together with Google Earth, that you can import a scaled aerial photograph directly from Google Earth, or use SketchUp to build models which can be seen in Google Earth.
  • 3Dtin – The simplest 3D software. You can draw directly from your browser.
  • Blender – Blender is the free open source 3D content creation suite, available for all major operating systems under the GNU General Public License. Blender was developed as an in-house application by the Dutch animation studio NeoGeo and Not a Number Technologies (NaN). It is a powerful program contains features that are characteristic of high-end 3D software.
  • OpenSCAD – OpenSCAD is a software for creating solid 3D CAD objects. It is free software and available for Linux/UNIX, MS Windows and Mac OS X. it does not focus on the artistic aspects of 3D modelling but instead on the CAD aspects.
  • Tinkercad – Tinkercad is a new and faster way of creating designs for your 3D printer. With only three basic tools you can create a wide range of useful things. Once your project is ready simply download the STL file and start your 3D print.

Check out the more software in the free software list.

Commercial software such as CAD software AutoCAD and Pro Engineer, software packages Rhino, Maya, and SolidWorks are all pretty good for designing 3D models.

http://www.instructables.com/id/Design-and-print-3d-models/

The 3d printing service I use is called Shapeways. They have a large selection of materials and a great user support base, as well as frequent updates to their website and material library, and low prices. (Very important!) However, there are many options out there and it is up to you to decide which one you like best.

In 3d printing, two important issues to take into consideration are minimum wall thickness and detail. These measurements vary based on the printer used and the material used.

Minimum wall thickness is how thick the thinnest part of your object is. Your object has to be thick enough to print in the desired material. You also need to take into consideration how thick supporting parts of the model are. For instance, if I was to make a wine glass out of stainless steel (why not?) and I made the stem 1 mm thick, it wouldn’t be strong enough to support a large structure above it. But if I changed the stem thickness to 5 mm, it would be much stronger.

Detail level is also important to take into consideration because 3d printers can only create detail down to a certain level. Just like regular printers, they do not have unlimited resolution. So you need to do some research about your 3d printer to determine how much detail your object can have. For moving parts you also need to take into comparison the clearance in between parts, to ensure they are not accidentally fused during the printing process.

All of this is based on what material you decide to use. Different materials have different minimum wall thicknesses and detail levels, as well as clearance thresholds.

Information regarding the different materials available via Shapeways, as well as specifications about detail, clearance, and wall thickness, can be found here andhere. Also be sure to check out their community forums for help and advice.

In order to print properly, you must export your model into the proper file format. Shapeways supports .stl, .dae, .x3d, .x3db, wrl, zip and x3dv. I usually export my models as .dae, simply because I know that it is a filetype that works.
Picture of Upload
screenshot.12.jpg
The process for uploading a file to be printed varies based on what printing service you prefer. I will walk you through uploading a file to Shapeways.First you must create an account. Simply click the “Sign Up” button in the top right of the home page, and complete the signup as you would on any other website.

When you have completed signup, return to the home page. If you are not logged in, do so at this time. To upload your model, press the pink “Upload” button underneath your username (your username is displayed where the “Sign Up” button previously was.)

The upload process is fairly simple. Press “Browse” and select your file. Enter a title and a description. Then select which galleries and categories you want your model to be in, and add some tags. Check the two boxes at the bottom and press “Upload.” within about 5 minutes you will receive an email telling you if your model was uploaded successfully or not. If it was unsuccessful, Shapeways provides some online tools to help you fix your problems.

Once you checkout it will take around 10 days (their shipping estimates may have changed since my last order) for your model to arrive.

101 interesting Technical Drawing Exercises to improve your practical skills FAST

101 practical cad exercises for beginners

Viktor Rask has written a very practical book where he introduces 101 technical drawings to beginners or anyone who wants to improve their speed and efficiency in drafting. At this end of this article, there is a special code for AllaboutCAD readers to get this book at a discount price.

But first, let me introduce some background information of the author.

Viktor is a mechanical engineer from Sweden and just like you, he has always been interested in learning more about CAD. At first, he started watching tutorials on Youtube and trying his best to copy what they did. He even did a couple of CAD courses at my university. While he learnt alot from those experiences, it did not prepare him enough for actual work in the industry. His practical skills never improved.

When he first started working, he was a third of the speed his colleagues were… not because he didn’t know how to do certain things but because he had no practice in drafting. His practical skills never improved from watching Youtube and reading theory.

After a while he finally figured out why… In his own words, he admits ” I never actually put in the time to practice, I was too lazy to go around and measure things in my home and I couldn’t find any technical drawings suited for my skill level online. I never practiced on actual technical drawings.

He puts his experiences and the exercises he had to do to improve his own skills in this practical e-book. While mainly aimed at beginners, this ebook also work wonders for individuals that do not consider themselves beginners but still want to improve their speed.

This book provides you with 101 technical drawings that you can practice your skills on to:

  • Increase your CAD proficiency.
  • Increase your confidence working with your preferred software.
  • Increase your technical speed.

The statistic says it all. About 80% of those that practice with this book see massive improvement in CAD speed in just a few exercises. This book is your “Go To” practice materials that will help you get better at CAD in a way that is interesting for you.

  • No more measuring things in your home before you can practice
  • No more finding technical drawings online that are way too complicated

Normal RRP for this ebook is $12.99. For the month of August and September 2019, use the coupon code “allaboutcad” to get the book for $9.49. That’s over 25% discount. Click this link or the image below to find out more

101 cad exercises and inclusions
101 CAD exercises – Only $9.49 for a limited time

(Full disclosure: we receive some commission for sales of this e-book)

Autocad Tutorial: Using Xref effectively for grid system on floor plans

Xref in AutoCAD means ‘external reference’ to other drawing files. One file can reference many other files and display them as an overlay (or background) on the main file.

Xrefs are usually used in larger projects to manage complexity of the main files, however, it is also beneficial in smaller and less complex projects where greater control of information layering is required.



In this example, we will look into creating a simple Xref of grid system for a floor plan:

  • Create a drawing file containing grid lines,  grid tags and general dimensioning                                      
  • Save file with an identifier name (i.e. 0-FP-A-GRID.dwg) and preferably under the same folder as the project file
  • In the project folder, create and open a new drawing file where the floor plan will be drawn In this case, we will name the floor plan file as 0-FP-A-UL.dwg
  • In 0-FP-A-UL.dwg, click Insert/External References
  • This will bring up the ‘External References’ window as follow. Pull down the ‘DWG icon’ on top right corner, select ‘Attach DWG’
  • In the ‘Select Reference File’ window, select the grid file 0-FP-A-GRID.dwg and click ‘Open’
  • This will bring up ‘Attached External Reference’ window.  Check ‘Overlay’ under Reference Type and click ‘OK’
  • The grid file is now loaded into the floor plan file. It is recommended to assign a unique layer for the Xref file and have this layer locked to prevent accidental shift/moved from its origin
  • Building elements such as walls and columns can be drawn over the Xref file as follow with the grid lines as references
  • To manage Xref file, type “Xref” in the command prompt to bring up the ‘External References’ window again. Right click the Xref file for editing options (such as Unload) to temporary turning off the file or Detach to delete the file.

AutoCAD Tutorial: Create a rectangle with an adjustable corner

Have you noticed how grip-editing a viewport is different from grip-editing a rectangle?

When you grip-edit the upper-right corner of a viewport to stretch it, the viewport keeps its rectangular shape. You can freely choose your new corner location, so you’re not just scaling. You can change the proportion between the width and height, all without losing its rectangle-ness.

Stretching a viewport

Stretching a viewport



But when you grip-edit the upper-right corner of a rectangle, the rectangle is distorted. The rectangle doesn’t know that it’s supposed to remain a rectangle. AutoCAD just thinks of it as a 4-sided, closed polyline. Indeed, select it and check in the Properties palette (Ctrl+1) and you’ll discover that it is indeed just a polyline.

Stretching a rectangle in AutoCAD

Stretching a rectangle in AutoCAD

AutoCAD 2010’s geometric parameters can help you easily create a rectangle that knows it’s a rectangle. And, what is a rectangle? Well, “rect” means right, as in 90°. “Angle” is self-explanatory. So, we need to ensure that the angles will stay 90°.

Here’s how:

  1. Draw a rectangle.
  2. Go to Parametric tab> Geometric panel, and click the Perpendicular button.
  3. At the Select first object: prompt, click the top horizontal line of the rectangle.
  4. At the Select second object: prompt, click the left vertical line. You’ll see the Perpendicular icon near the upper-left corner of the rectangle.
  5. Repeat the process for the two lines that meet at the lower-left corner and the lower-right corner.

A rectangle with 3 perpendicular geometric constraints

A rectangle with 3 perpendicular geometric constraints

Note: If you try to do all 4 corners, you’ll get a message telling you that AutoCAD can’t apply the constraint. That’s because when you have 3 corners constrained to perpendicular, the last corner is superfluous, and is therefore an overconstraint.

You cant overconstrain an object in AutoCAD

You can’t overconstrain an object in AutoCAD

Now, you can grip-edit that upper-right corner and it will behave just like a viewport!

The rectangle now stretches like a viewport!

The rectangle now stretches like a viewport!

Here’s a quick video of the same operation:

Viewing 3D objects with Isometric View in AutoCAD

Ben RichardsonThis is a guest post by Ben Richardson. Ben is director of Acuity Training, a UK based IT training business. Acuity Training focuses on high quality classroom-based IT applications training including AutoCAD (of course!), Adobe and Microsoft.

You can’t succeed in 3D drawing without learning how to view your model from various angles. In this tutorial, you will become familiar with AutoCAD’s Isometric views, learning to move and alter AutoCAD objects in 3D. You will do this by creating a simple 3D representation of a door and manipulating it to suit your needs. It isn’t an exact model but will give you the experience you need to create more precise 3D models.unit



1) Specify settings

Before we start, you need to make sure your settings are identical to mine for the tutorial to work.

We’ll be working in inches. If you customarily work in the metric system, type DWGUNITS on the command line and type 1, for inches.

Type UNITS and in the Units dialog box, under Length, Type, choose Architectural and click OK.

To specify the Snap and Grid settings, right-click the Gridmode button on the Status bar and choose Grid Settings.

Snap and Grid should both be on, set to 6″, as you see on the right. Click OK to close the dialog box. Continue reading Viewing 3D objects with Isometric View in AutoCAD

Combine or subtract 2D shapes to create custom shapes

Sometimes you need to create a 2D profile that is a combination of the basic geometrical shapes that AutoCAD creates. While you might be able to use the PLINE command to create what you want, in some cases, 2 other methods may be easier.

Subtract shapes with the SUBTRACT command

For example, let’s say that you want to create this profile.

autocad-tips-region-custom-shapes-1

Depending on the information you have about the radius of the circle and length of its inset, it might be easier for you to start with these objects:

autocad-tips-region-custom-shapes-2



Here is one way to get the result you want: Continue reading Combine or subtract 2D shapes to create custom shapes

Working with linetype scales

Simple linetypes allow you to apply a repeating series of dashes, dots, and spaces to your objects. Complex linetypes can also include text or shapes.

Recently, a reader said that his linetype was defined as dash-dot but displayed as a continuous linetype. If you have this situation, zoom in and see if you can see the dots and dashes.



If you find that the linetype patterns in your drawing are too long or short, the line might look continuous. How often the pattern is repeated is affected by three factors:

  1. The linetype definition itself
  2. The global linetype scale
  3. The object linetype scale

1. Use a different linetype definition

autocad-tips-linetype-scales-1One choice is to change the linetype. A number of linetypes come in short, medium, and long variations, such as Dashedx2, Dashed, and Dashed2, as you see here.

Note: If you use ISO linetypes, the pattern definitions are much longer than the other linetype definitions, so you may need to make adjustments to the linetype scale.

2. Change the global linetype scale

Another choice is to change the global linetype scale, which affects all noncontinuous linetypes in your drawing. AutoCAD  multiplies the linetype definition by the global linetype scale to calculate the length of each repetition of the linetype:

  • Linetype scales larger than 1 result in longer sections — and fewer repetitions of the linetype definition
  • Linetype scales less than 1 result in shorter sections — and more repetitions of the linetype definition

Here you see 3 versions of a drawing with linetypes at linetype scales of 0.5, 1, and 2. As you can see, a scale of 2 is too large and a scale of 0.5 is too small. A scale of 1 is just right.

autocad-tips-linetype-scales-2a

When you draw, you just want to be able to distinguish the linetype both when you can see the entire drawing on the screen and when you zoom in close. The main reason to scale linetypes is for plotting. A linetype scale that works for a drawing of a house while you’re drawing may look continuous when you plot it at a scale factor of 1 = 192.

When plotting, first try the plotting scale factor for the linetype scale. If that doesn’t give you the results you want, try 1/4 or 1/2 of the scale factor — in the 1 = 192 example, you could try a linetype scale of 96 or 48.

To change the linetype scale, click the Linetype drop-down list in the Properties panel of the Home tab and choose Other to open the Linetype Manager. Click Show Details if the lower portion of the dialog box isn’t displayed.

In the Global Scale Factor text box, type the scale factor that you want. Click OK. The drawing regenerates, changing the scale of every noncontinuous linetype in the drawing.

autocad-tips-linetype-scales-3

Tip: The global linetype scale is stored in the LTSCALE system variable. You can change the linetype scale by typing ltscale on the command line and typing a scale.

3. Change the object linetype scale

Sometimes you may want the linetype spacing to be different for just 1 or 2 objects. Maybe an object is too small to show the linetype clearly.

To change the linetype scale, open the Linetype Manager. Click Show Details if necessary and in the Current Object Scale text box, type the scale factor you want. Click OK. Now all objects that you draw use the current object linetype scale. When you’re done drawing objects at that linetype scale, remember to change the linetype scale back to 1.

Tip: The current object linetype scale is held in the CELTSCALE system variable. You can also change the current object linetype scale by typing celtscale on the command line and typing a scale.

If you have also set the global linetype scale to a value other than 1, AutoCAD multiplies the 2  linetype scales. So if you have a global linetype scale of 12 and a current object linetype scale of 0.5, objects you draw will have a linetype scale of 6.

To change an existing object’s linetype scale, select the object and open the Properties palette. Click Linetype Scale and then type the new linetype scale. This linetype scale affects only the selected object. It does not affect the global linetype scale.

Have linetype scales frustrated you? Do you have any tips you can share? Leave a comment! And please use the Share buttons to share this with your colleagues.

Tutorial: Create a 3D model

This is a guest post by Andreea Georgiana. She is a CAD enthusiast who likes using the power of Computer Aided Design to create cool useful designs, from conception to 3D printing. She has a 21-day AutoCAD course at tutorial45.com.



She says, “Being able to use Computer Aided Design software to bring your ideas to life is one of the things I totally disagree only engineers should be able to do. With the numerous advantages of being able to move past the level of a 3D model to actually having the model 3D printed, anyone should consider learning at least the basics of modifying a CAD model.

“As a CAD hobbyist, wife and mother, I have found many cases where a customized solution designed myself has solved a problem in the exact manner I wanted, thanks to the power of CAD and 3D printing. You can find some free tutorials here.”

* * * * *

Before I start, here are 2D and 3D images of the model you’ll draw in this tutorial,

autocad-tips-draw-3d-model-1a

autocad-tips-draw-3d-model-1b

Continue reading Tutorial: Create a 3D model

3D AutoCAD Tutorial: Create a 3D piston

This is a guest post by Viktor Rask, founder of CAD Mode and author of the e-book 101 CAD Exercises – Learn & Improve Your Skills. He is a mechanical engineer (BSc.) with a passion for CAD and 3D! He also loves to help others grow.



* * * * *

autocad-tips-3d-piston-final-1When I first started to learn CAD a few years back, I had a major problem with my learning process. I couldn’t find any exercise material. I searched and searched but couldn’t find anything useful. I decided to create the 101 CAD Exercises book to help others speed up their learning process and make it more hands-on and fun. If you want more exercises like this, you can get them here. (The exercises are 2D and 3D drawings without instructions so that they are not specific to AutoCAD.)

In this tutorial, you will learn how to create a piston using 3D geometry in AutoCAD. To do this you will use the 2D drafting and annotations and the 3D features. I assume that you are already a bit familiar with the basic 2D drawing commands such as LINE, CIRCLE, TRIM, etc. The final model should look something like this in 3D.

Here are the 2D drawings:

autocad-tips-piston-final-2D

Remember that using gridmode (F9) and snapmode (F7) can be helpful between drawing tasks. For this exercise, I’ve been using AutoCAD 2017 but it will work with previous versions as well as other CAD software. Your commands and shortcuts might differ with other versions, though. The dimensions that are used in this exercise are originally metric but since it’s all proportional you can use the same values but with imperial units instead. I’ve decided to keep the measurements unitless for this exact reason.

  1. Start a new drawing in AutoCAD.
  2. Draw a circle with a diameter of 60 and place its center on the origin (0,0).
  3. Draw a horizontal line that starts at the origin and a length of 23. This line will be used as a reference length for the next step.

autocad-tips-circle-line-2

  1. Draw a rectangle using the RECTANG command as shown on the right side of the image below, using the endpoint of the line as a guide to place the rectangle. The dimensions of the rectangle don’t need to be exact but they must exceed the circle perimeter as we use it as a cutter. Then mirror the rectangle using the start point of the line (or the center of the circle) for the mirror line. Remember to erase the reference line that you used to create the rectangle.

autocad-tips-3d-piston-cutter-3

  1. Now draw a concentric smaller circle with a diameter of 52. Also, draw a vertical line 19 units to the right of the center of the circles as shown below and mirror it. As with the rectangles, the lines need to exceed the circle perimeter.

autocad-tips-lines-4

  1. Now use the TRIM command and use the vertical lines as edges to trim the inner circle. Resize the 2 vertical lines so that they end at the top and bottom arcs. Then use the JOIN command to make the following shape in the center.

autocad-tips-trim-5

  1. Click the gear (Workspace Switching) icon on the bottom right of the screen and choose 3D Basics instead of Drafting and Annotation. Also choose a 3D viewpoint so you aren’t looking at plan view.
  1. Now use the EXTRUDE command to extrude the shapes to make a 3D model. The Z dimensions (shown below) are 40 units for the rectangles, 44 units for the central shape,  and100 units for the circle. This image is using the X-ray visual style.

autocad-tips-extrude-6

  1. Now start the SUBTRACT command and subtract every shape from the main cylinder. Remember that first you must select the main cylinder, press Enter and then select the objects you want to subtract from it. You might need to change your viewpoint or visual style, especially to subtract the central shape. Now you should have a model looking like this:

autocad-tips-subtract-7

  1. Now you should go back to the 2D Drawing and Annotation and return to a top 3D view such as SE Isometric if necessary. Draw a concentric circle with a diameter of 52 and a rectangle (using the RECTANG command) with a height of 7.5 and one of its sides on the x-axis as shown in the image. The length of the rectangle should exceed the cylinder diameter, which is 60.

autoad-tips-line-circle-8

  1. You can isolate (hide) the main body by right-clicking on it and choosing Hide or Isolate>Hide. Then use the COPY command to create two more circles, 44 units and 100 units in the z-direction. After this, delete the base circle. Go back to the 3D Basics workspace.

autocad-tips-3-circles-9

  1. Use the EXTRUDE command on the 2 circles; the lower circle should be 42 units upwards and the circle on top should be 10 units downwards. Then use the REVOLVE command on the rectangle to make another cylinder. Specify the X axis as the axis of revolution and use the default 360° revolution.

autocad-tips-revolve-10

  1. Now right-click and end object isolation (Unhide). Using the MOVE command, bring the thin cylinder 20 units upwards in the Z-direction and move it towards the main body of the piston so that it extends on both sides.

autocad-tips-move-11

  1. Now subtract the 3 cyllinders from the main body. You can use the Bottom view for easier access.
  1. In the 2D Drawing & Annotations workspace, draw a concentric circle with a diameter of 20 units. Use the EXTRUDE command to create a cylinder that is higher than the main body.  Then subtract it from the main body.

autocad-tips-subtract-12

  1. Now use the CHAMFEREDGE command pick the outer edge of the top face of the cylinder, press Enter and type d to give it a distance from the edge. Choose 1 unit as the distance and then press Enter. You must enter the distance twice to give it the same distance from both edges.
  1. Start the FILLETEDGE command and then pick the inner edge of the top face of the cylinder, press Enter, and type r to give the fillet a radius. Choose 1 unit as the radius and press Enter.

autocad-tips-subtract-cylinder-13

  1. Next task is to fillet the side faces. Use the same command as in the previous step.

autocad-tips-fillet-14

  1. We will now create the ring pockets on the piston’s outer wall. Use the TORUS command. Set the center of the torus to the origin (0,0) and then use 60 units as the diameter and 3 units as the thickness. Make three copies of the torus (using the COPY command) with the following values in the z-direction: 76, 83 and 90 units.

autocad-tips-rings-16

You should delete the first torus. Remember that you can isolate (hide) the main body for this step.

  1. Finally, subtract the tori (plural of torus) from the main body. You should now have a 3D model that looks like the one at the beginning of this post.

For more drawings that you can use to practice your skills, be sure to check out my book!

If you have any questions you can also email me at viktor@cadmode.com and I’ll do my best to help you out.

Do you have any tips to help make this tutorial easier? Did you find this tutorial helpful? Leave a comment! And please share the knowledge using the Share buttons below!

Slim down your drawings with the PURGE command

autocad-tips-purge-2Are your drawings bloated for no obvious reason? When you insert a block, is there a long list of blocks that aren’t in the drawing? Ditto for layers?

Oversized drawings load more slowly, take up more storage space, and take longer to save.



Then you need the PURGE command!

Yes, you want slim drawings

Definitions of blocks, layers, styles, and more that aren’t actually used in the drawing make it slow and cumbersome. The PURGE command finds named components that aren’t used and lets you delete them. In a complicated drawing, there can be dozens or even hundreds of unused layers, blocks, text styles, dimension styles, and more.

To start the PURGE command, choose Application Button, Drawing Utilities, Purge or just type purge on the command line. The Purge dialog box opens. Components that have unused items have a plus sign next to them. In this figure, you can see that there are unused blocks, dimension styles, layers, and linetypes. You can expand these items to see what you can purge.

autocad-tips-purge-1

Specify PURGE settings

Continue reading Slim down your drawings with the PURGE command