Trim, Extend, Divide, Delete

Exercise 29 – Trim, Extend, Delete

When drawing by hand, you must attempt to place each line perfectly to prevent excessive rubbing out using an eraser or scratching out using a blade, however using CAD there is no need to be concerned about that at all because you can change your drawing at any time to correct entities that are too short, too long or shouldn’t be there.

Whilst the following exercises are quick and easy, don’t dismiss the importance of how and when to use them to your best advantage. Good use of these tools will make a big difference to the speed that you can produce your drawings.

  1. Open the file ‘Trim-Extend-Divide-Delete’ to reveal the following drawing.

  2. Select the ‘Trim, Extend, Divide, Explode… Then the ‘Trim’ command. Look at the prompt.

  3. Select near one end of one of the 4 orange lines in drawing ‘b’ and then move your cursor up and down. Watch as the selected line follows to indicate if the line is to be lengthened or shortened.

  4. Click on the blue line, making sure you have a diamond cursor, and the orange line will be trimmed back to the blue line.
  5. Repeat for the next orange Line, only this time instead of selecting the blue line to trim to, simply pick a point in a blank area of the drawing , and the line will be trimmed (longer or shorter) to be perpendicular with that point.

Extend

Whilst the command is called ‘Trim’, the same command is used to extend lines and arcs too.

  1. Repeat for the remaining two orange lines.

The end nearest to where you select the entity to be trimmed is the end that is lengthened or shortened.

  1. Try the command on the blue Curve in drawing ‘h’. Trim each end back to the magenta Arc.
  2. Now try the Orange curve

Curves cannot be made longer using this command as there is no precise mathematical direction for the curve to extend to beyond its current position.

  1. Use Undo to step back multiple times to the very beginning of this exercise
  2. Be sure you’re in neutral. Now select all four Orange lines of drawing ‘b’ and then select the ‘Trim’ command again. Look at the prompt.
  3. As you move your cursor you will notice that the end points of the selected lines are highlighted and change ends depending on the location of your cursor.
  4. When all the points are on the upper end of the lines, click the left mouse button to accept.
  5. Now select the Blue line and all four lines will be trimmed at once to the blue line. J
  6. Repeat the command for the blue lines in drawing ‘c’ and trim them all back to the black curve.

Before or After

Pick the command before the entity to trim one at a time; or Pick the entities before the command to trim multiple entities at the same time.

  1. Again, use Undo to get back to the where we started.

Shortcut

Right click when your cursor is over an entity and select the Trim option from the menu that appears.

Keep the file open for the next exercise.

Exercise 30 – Trim/Extend to Corner

The next command, ‘Trim to a Corner’ basically trims or extends two entities at the same time until they meet each other.

  1. Select the command.

  2. Using the same ‘Trim-Divide-Delete’ file, zoom in to drawing ‘d’.

  3. Work your way around the drawing, clicking on each of the entities so they join into a corner. Start with the bottom end of the vertical magenta line and the left end of the light blue horizontal line.

You’ll notice lines and arcs will extend longer or trim shorter until they meet the other entity selected. You must be mindful of which end of the line you’re selecting as it is the end nearest to your selection point that gets trimmed.

  1. Corner the top end of the purple arc with the right end of the black horizontal line.

What happens, nothing? This is because they don’t actually join. If you continue the arc around its path it does not touch the line.

Corner trimming is a great way of making sure that lines join end to end which you will need when inserting a hatch pattern/plane into an enclosed outline, which you will be doing later.

Keep the file open for the next exercise.

Exercise 31 – Trim/Extend Length

This is a great tool to make an entity a specific length or add or subtract a length from an entity.

  1. Select the command and the following dialog appears.

  2. Set the dialog as shown and then start selecting lines, arcs, curves and circles to see what happens.
  3. When you’ve finish ‘playing’ with this command repeat it, only this time set it as follows

  4. And again click on various entities in the drawing to see what happens.
  5. Now set the dialog as follows, using -50 as the value and try it out.

Super-Hot Tip

To repeat the last used command, press Enter. This tip may be more useful to you than almost all the others.

Keep the file open for the next exercise.

Exercise 32 – Divide by Entity

The next commands are almost the same as the Trim commands except they divide rather than trim.

  1. Select the command.

  2. Using drawing ‘b’ again select one of the orange lines and then select the blue line.

The orange line has been divided by the blue line.

  1. Go to neutral (no command selected) and then select the same orange line again. Notice this time that the line you’ve selected is only part of the original line.
  2. Select all the remaining orange lines and then select the command again. Now choose the blue line. All the selected lines will have been divided by the Blue line.

You can’t tell if an entity has been divided until you select it because it leaves both divided parts on screen without deleting them.

Keep the file open for the next exercise.

Exercise 33 – Divide by Length

This command allows you to divide an entity at a certain distance along from the end nearest to where you select it.

  1. Select the command.

  2. Enter 35 as the divide length.

  3. Again, select any of the lines, arcs or curves.

 

  1. When you’ve finished selecting, right click a few times or press Esc a few times to return to neutral.

 

  1. Now individually select the entities you divided.

You will see that they’ve been divided by the distance of 35 from the end nearest to where you selected.

Keep the file open for the next exercise.

Exercise 34 – Divide by Number

This command allows you to divide an entity at a certain distance along from the end nearest to where you select it.

  1. Select the command.

  2. Enter 5 as the number or section to create

  3. Again, select any of the lines, arcs or curves.

Temporary points appear at the break points along the entities. These points disappear if you refresh the screen by zooming or panning or repainting etc.

  1. When you’ve finished selecting, right click a few times or press Esc to return to neutral and individually select the entities you divided.

 

You will see that they have been divided into 5 equal length sections. If you selected short 35mm lines from the previous exercise you will see that that segment was divided again. If you double click on a segment it will open a dialog box showing its properties. You can then see the length value.

Undo as many times as required to get the drawing back to the beginning. Or reload the file by selecting File from the menu, and select the last opened file. ….Trim-Divide-Delete.cad

Keep the file open for the next exercise.

Exercise 35 – Break Delete

This command allows you to divide an entity by two other entities or positions and delete the segment divided between the two positions

  1. Zoom in to Drawing ‘c’

  2. Select the command and look at the prompt

  3. Select one of the blue parallel lines, and then select the red line. Finally select the curve.

If you had picked a position in the drawing rather than the line or curve, the blue line would have been divided at a point perpendicular to that position.

  1. Repeat the same command for the remaining blue lines.

Undo as many times as required to get the drawing back to the beginning. Or reload the file by selecting File from the menu, and select the last opened file. ….Trim-Divide-Delete.cad

Keep the file open for the next exercise.

Exercise 36 – Delete

  1. Select a bunch of entities the press Delete (Fn + Backspace) on the keyboard. They will disappear.

  2. Select a few more entities then select the Delete trash-can

  3. Select a few more entities then select Edit, Cut from the drop-down menu.

THIS TIME LOOK AT THE PROMPT for what it’s asking, and then select a position in the drawing to use as the origin of the selected entities. You can think of the Origin as a ‘handle’ that you’re grabbing the entities by.

The selected entities will disappear from your screen like the other methods but will still be held in memory ready for you to ‘paste’ somewhere else in this or another drawing.

When you Edit, Paste you’ll be asked for a position to paste the entities. Using the ‘handle’ you you’ll be able to accurately position the pasted entities.

This is a simple but powerful tool.

Shortcut

Use Ctrl + X (Command + X) instead of the Edit, Cut dropdown menuUse Ctrl + V (Command + v) instead of Edit, Paste.Cutting and Pasting this way can be an excellent method to move entities from one place to another accurately.
Remember to set your Origin position when using these commands.

Undo back to the beginning again.

Keep the file open for the next exercise.

Exercise 37 – Magic Eraser

In this exercise we use the same file we have been using, the Trim-Extend-Divide-Delete file.

The idea of this exercise is to explore the power of the Magic Eraser. This unique tool can be used to erase (delete) and trim.

  1. To set the drawing up correctly we need switch on all the layers, so do that first.

Notice that the drawing now shows a series of numbers. We’ll use these numbers to assist in exploring the Magic Eraser tool.

Be sure no command is running. I.e. you’re in Neutral. Check the Prompt; it should say:

  1. Hold down the Alt key and then click the left mouse button and drag the crosshair from number 1 to number 2 in drawing ‘a’ (as indicated by the black line below) …then release the mouse button

Don’t Let Go

Do not release the keyboard key until AFTER you release the mouse button!

All the entities in this first example will be deleted because they are free standing; they are not crossed by any other entities.

  1. Repeat for example ‘b’ in your drawing as shown below.

Because the blue line crosses the orange lines, those parts of the orange lines touched by the Magic Eraser are trimmed back to the blue line.

  1. Repeat the command for the remaining examples to get used to it.

Linear Only

Like the Trim and Divide command this tool only selects linear entities such as lines, arcs, circles, curves and ellipses. It will not select Text, Planes, Components, Groups or Dimensions.

Now we can look at a more advanced example

  1. Open the file called ‘Magic-Eraser-2’ to reveal the following drawing.

  2. Now use the Magic Eraser to trim and delete, to produce the following.

  3. When complete, Use File Save-As and save this file as My Magic Eraser Training

Exercise 38 – Fillet and Chamfer

To expand on the concept of trimming and extending CAD allows you to fillet (round off) or chamfer (cut off) corners in a drawing. It automatically trims or extends entities and at the same time inserts new ones. You don’t have to worry about working out how to do it, RealCAD does it for you!

  1. Open the drawing file called ‘Cutting-Corners’.

  2. Select the Radius fillet arc command as shown below

  3. Set the fillet radius to 10 in the dialog, then click OK (or press Enter for added speed).
  4. Click on each of the two lines as indicated by the positions 1 and 2. Be sure you have a diamond cursor when selecting in this exercise.
  5. Repeat for the two lines at positions 3 and 4 and then Right click once to stop the command.
  6. Reselect the Radius fillet arc command from the icon menu (or just press Enter on the keyboard to repeat the last command)
  7. Set the radius to 20 and click OK.
  8. Select the lines at positions 9 and 10, then 11 and 12. Select the two arcs where indicated at the numbers 13 and 14. Then select the curve and arcs at 7 and 8, then 5 and 6.
  9. Right click once to stop the fillet command.
  10. Select the Chamfer icon command as shown below

  11. Set the dialog options to match those shown below and click OK.

  12. Select the two lines where indicated at positions 15 and 16.
  13. Right click once to stop the chamfer command.
  14. Reselect the Chamfer command, only this time change the ‘Chamfer distance along line 1’ setting to 40 and click OK.
  15. Select the two lines where indicated by the numbers 17 and 18.
  16. Right click once to stop the chamfer command.
  17. Select the Insert chamfer command again. Select the ‘Length of chamfer’ option and set the ‘Chamfer length’ to 10, then click OK.
  18. Select the two lines where indicated at the positions 19 and 20, then 21 and 22
  19. Save the file as ‘My Corner Training’

Easy!

Exercise 39 – Node Dragging

You may have noticed when you select a single entity, small squares appear that relate to that entity. They appear at the ends of a line, the centre and ends of arcs, the centre and circumference of circles and at the ends and either side of curves and also on dimensions.

These small squares are referred to as ‘Nodes’ or ‘Handles’ and they can be very useful for manipulating the entities they belong to. They only appear when a single entity is selected.

  1. Open the file ‘Node-Dragging

The idea of this next exercise is to select each red entity one at a time and drag its nodes to make the red drawing look like the blue drawing.

  1. Start with a line on the left and drag its nodes over the end of the other line until you see a Square cursor, then release the mouse button. Continue with all the other entities to move them to desired positions and sizes.

If you want to get things really straight and lined up, switch the Grid on.

  1. When complete save the drawing as ‘My Node Training’.

Exercise 40 – Curve Handles

  1. Open the file named ‘Curve-Handles

The outside edge is a single curve that starts and ends at the same point. It has been filled in with a surface plane to help distinguish the shape.

  1. Select the curve and notice the node points that control the curve’s shape as you noticed with the letter ‘S’ in the previous exercise.

Difficult Pick

Having difficulty selecting the red curve instead of the aqua plane? Move your cursor a little and try again or use selectability settings to prevent the selection of planes or aqua colour at all

  1. Drag some of the node points to a new location to create a new shape

  2. Be sure the curve is selected and then choose the Offset by distance command from the Transform menu

  3. In the dialog enter 3000 and click OK

 

  1. Check the prompt

  2. Now simply click on the outside of the shape to indicate which side of the curve you wish to offset.

On slow computers you may need to wait a short while whilst the software calculates a perfect offset of the curve…

  1. Press the right mouse button several times to finish the command and unselect the original curve. You should then be in neutral.
  2. Select the new offset curve and use node dragging to join its two ends.

You may notice that the offset curve has many more control points than the original curve. This is to ensure a more accurate offset.

  1. Save the drawing as ‘My Curvy Thing

Bonus Exercise – Fashionable Curves

Open the drawing file called ‘Fashionable-Curves’ from the training folder.

When you’re happy with your designs save your file as My Fashion Statement

Notes

The curves in the top row of ladies have been Grouped together to prevent them from being selected by mistake.