Working in AutoCAD often involves managing multiple layers, each potentially containing various elements of a design. There may be times when many or all of these layers are frozen to simplify the workspace or enhance performance. However, it’s equally important to have a quick and efficient way to thaw all these layers when necessary. This tutorial will guide you through creating a handy AutoLISP program that looks at each layer that is defined in the current drawing and thaws it. It prints a message that all layers are thawed.
AutoLISP Tutorial 16: Thawing All Layers in a Drawing
ObjectiveYour task is to create an AutoLISP program that performs the following functions:
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Specifications:
- Begin by ensuring that the command echoing is turned off to provide a seamless user experience. Remember to restore its original state at the end of the program.
- Utilize the tblnext function to loop through all the layers in the drawing. This function should aid in identifying every layer present.
- For each identified layer, you will need to thaw it. Remember, thawing a layer means making it visible and editable.
- Once all layers are processed, print the message to the user notifying that all layers have been thawed.
Hints:
- You might want to consider using a loop structure to go through each layer until no more layers are found.
- The layer name will be useful when issuing the command to thaw the layer.
Outcome:
By the end of this exercise, you should have a fully functional program that ensures all layers in the current drawing are thawed and then notifies the user about the completion of the task.
AutoLISP Tutorial 16 Solution: Thawing All Layers in a Drawing
This solution walks you through the creation of an AutoLISP program aimed at thawing every layer present in the current drawing. After the layers are thawed, the program will notify the user about the action performed. The solution will highlight key lines of the code and explain their purpose and functionality.
Program:
| (defun C:TUTO16 ( / svcm stp1 stp2 layt layn) (setq svcm (getvar “cmdecho”)) (setvar “cmdecho” 0) (setq stp1 1) (setq stp2 1) (setq layt 1) (while (= stp1 1) (setq layt (tblnext “layer” stp2)) (setq stp2 nil) (if (= layt nil) (setq stp1 0) (progn (setq layn (cdr (assoc 2 layt))) (command “LAYER” “t” layn “”) ) ) ) (princ “\nAll Layers have been thawed”) (setvar “cmdecho” svcm) (princ) ) |
Explanation:
(setq svcm (getvar “cmdecho”)): This line stores the current state of the command echoing in the svcm variable.
(setvar “cmdecho” 0): Command echoing is turned off to ensure a seamless user experience when the program runs.
(setq stp1 1), (setq stp2 1), and (setq layt 1): Initializes control variables for the upcoming loop and sets up for the layer iteration.
(while (= stp1 1): Begins a loop that will iterate through each layer in the drawing.
(setq layt (tblnext “layer” stp2)): Using the tblnext function, this line fetches the next layer in the drawing.
(setq stp2 nil): Resets the initialization variable for tblnext to ensure the function fetches the next layer in subsequent iterations.
(if (= layt nil): This condition checks if there are any more layers left in the drawing.
(setq layn (cdr (assoc 2 layt))): If there are more layers, this line extracts the name of the current layer.
(command “LAYER” “t” layn “”): Issues a command to thaw the current layer using its name.
(princ “\nAll Layers have been thawed”): Once all layers are thawed, this line prints a message to the user.
(setvar “cmdecho” svcm): Restores the original state of the command echoing.
Conclusion:
You’ve successfully created an AutoLISP program that ensures all layers in the current drawing are thawed. This program is efficient and user-friendly, turning off command echoes to provide a smooth user experience and restoring them at the end. It’s crucial to understand the logic and functions used in this program as they form the foundation of many other AutoLISP tasks you might encounter in the future.