Currently, in QCAD, adding precise measurements to line drawings is cumbersome. You either need to change the length in the Properties dialog box after drawing, or start a line, click somewhere on the canvas, and then manually enter the desired length in the toolbar.
This process is frustrating and time-consuming, especially for users working with detailed drawings. It would be highly beneficial if QCAD allowed dynamic measurement input directly when drawing lines, similar to how many CAD programs let you type the exact length as you draw. This would streamline workflow and improve precision.
Thank you for considering this feature.
Feature Suggestion: Dynamic Measurement Input for Lines
Moderator: andrew
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Re: Feature Suggestion: Dynamic Measurement Input for Lines
Please refer to our tutorial 2.1 Keyboard Shortcuts which also covers direct entry of values:
https://qcad.org/en/tutorial-2-1-keyboard-shortcuts/
Drawing a line with an entered length is covered from about 3:07.
https://qcad.org/en/tutorial-2-1-keyboard-shortcuts/
Drawing a line with an entered length is covered from about 3:07.
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Re: Feature Suggestion: Dynamic Measurement Input for Lines
Hi,
For a line tools globally?
Let us consider first 'Line from 2 points' (LI) in segment mode with a recent QCAD release.
Defining a first position is mandatory, the line has to start somewhere. Not?
I can't envision how to skip this step.
That can be by indicating a position on the canvas with the cursor or by keying in a coordinate in the Command Line.
QCAD accepts various coordinate formats.
Indicating a next position on the canvas with the cursor is already dynamical IMHO.
The preview of the line segment to create adapts with the new cursor position.
For this next position you can also key in a second coordinate.
Using the relative polar notation you specify a fixed length.
The former used coordinate is typically the relative zero, in this case that is the first point you have just defined.
You can also set a preference that coordinate entries are always relative.
QCAD also supports 'Direct Distance Entry' by keying in only a value in the Command Line.
riverbuoy aka Robert S. is the best person for explaining that to you.
You don't have to additionally install his contribution, it was already implemented in 2013.
Or you could search on the forum for the terms 'Direct Distance Entry'.
Keying in a distance in the Command line or in the Option Toolbar sounds as the same effort for me.
Hitting the Space-bar sets the focus on the Command Line.
Ctrl+Space-bar sets the focus on the first value input field of the Option Toolbar.
Remark that if you just start typing in something numerical it is automatically send to the first input field on the Options Toolbar.
Conveniently that is the Length value field for LI.
The Length option may not be active, use the shortcut .L to toggle its state.
I remark indeed that the Length and Angle checkbox state are not stored persistent between usage. 
As last I would add that you can also force the Angle-Length restriction with EL.
If I left something out then other users or Andrew might jump in.
The title of your post may also be associated with using a measurement as base for the Length.
R-click on the Length value option or on the Command Line to enter a variable defined with a measurement method from the list.
You won't know the actual value of the variable unless you query it, but it will be reasonable exact.
That a numerical input improves precision is debatable.
Values in the Property Editor are typically rounded, avoid copy/paste for not so nice values or when they only look neat as rounded.
Values listed in the Command Line history by Info tools are also rounded or truncated.
It is already an advantage that QCAD can evaluate simple to very complex expressions in value fields.
Then snapping to positions, intersections and so on, is as good as it gets in full floating point.
I still need to be convinced that keying in everything only using the keyboard is more efficient.
It is called a Graphical User Interface (GUI) for some reason.
Beats a textual UI all the time.
The analog would be entering the command 'Swipe Left' or 'Scroll down' on your (not so) Smart Phone.
Regards,
CVH
For a line tools globally?
Let us consider first 'Line from 2 points' (LI) in segment mode with a recent QCAD release.
Defining a first position is mandatory, the line has to start somewhere. Not?
I can't envision how to skip this step.
That can be by indicating a position on the canvas with the cursor or by keying in a coordinate in the Command Line.
QCAD accepts various coordinate formats.
Indicating a next position on the canvas with the cursor is already dynamical IMHO.
The preview of the line segment to create adapts with the new cursor position.
For this next position you can also key in a second coordinate.
Using the relative polar notation you specify a fixed length.
The former used coordinate is typically the relative zero, in this case that is the first point you have just defined.
You can also set a preference that coordinate entries are always relative.
QCAD also supports 'Direct Distance Entry' by keying in only a value in the Command Line.
riverbuoy aka Robert S. is the best person for explaining that to you.
You don't have to additionally install his contribution, it was already implemented in 2013.
Or you could search on the forum for the terms 'Direct Distance Entry'.
Keying in a distance in the Command line or in the Option Toolbar sounds as the same effort for me.
Hitting the Space-bar sets the focus on the Command Line.
Ctrl+Space-bar sets the focus on the first value input field of the Option Toolbar.
Remark that if you just start typing in something numerical it is automatically send to the first input field on the Options Toolbar.
Conveniently that is the Length value field for LI.
The Length option may not be active, use the shortcut .L to toggle its state.


As last I would add that you can also force the Angle-Length restriction with EL.
If I left something out then other users or Andrew might jump in.

The title of your post may also be associated with using a measurement as base for the Length.
R-click on the Length value option or on the Command Line to enter a variable defined with a measurement method from the list.
You won't know the actual value of the variable unless you query it, but it will be reasonable exact.
That a numerical input improves precision is debatable.
Values in the Property Editor are typically rounded, avoid copy/paste for not so nice values or when they only look neat as rounded.
Values listed in the Command Line history by Info tools are also rounded or truncated.
It is already an advantage that QCAD can evaluate simple to very complex expressions in value fields.
Then snapping to positions, intersections and so on, is as good as it gets in full floating point.
I still need to be convinced that keying in everything only using the keyboard is more efficient.
It is called a Graphical User Interface (GUI) for some reason.
Beats a textual UI all the time.
The analog would be entering the command 'Swipe Left' or 'Scroll down' on your (not so) Smart Phone.
Regards,
CVH
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Re: Feature Suggestion: Dynamic Measurement Input for Lines
Big thanks to the both of you, ctrl + spacebar is my go to from now on. Using the command line I need to erase the figure each time, but in the tool options it automatically selects the whole fugiure and I just overwrite it. This is an absolute time saver. Thanks again guys!
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Re: Feature Suggestion: Dynamic Measurement Input for Lines
Hi,
Agreed, hitting Space-bar could perhaps pre-select what already is in the Command Line ...
Try:
- LI and indicate a start point.
- With the focus still on the canvas type 12 and indicate the direction.
- Type 25 and indicate the direction for the second segment.
Then you don't really need to set the focus on the Option Toolbar.
When the focus is on the canvas, typing in a numerical value is send to the first input field of the Options Toolbar.
Other not well-known features:
Hold down the Alt key for momentarily restrict orthogonal when indicating a position with the cursor.
Or use EO, EH or EV for that matter, active until EN.
While selecting the Alt key lets you choose from stacked entities if any.
Holding down Ctrl or Shift in combination with the mouse wheel pans in one direction.
Pushing on the wheel pans freely.
But this still eludes me:
Sounds like a relative polar coordinate to me.
Regards,
CVH
Agreed, hitting Space-bar could perhaps pre-select what already is in the Command Line ...
Try:
- LI and indicate a start point.
- With the focus still on the canvas type 12 and indicate the direction.
- Type 25 and indicate the direction for the second segment.
Then you don't really need to set the focus on the Option Toolbar.
When the focus is on the canvas, typing in a numerical value is send to the first input field of the Options Toolbar.
Other not well-known features:
Hold down the Alt key for momentarily restrict orthogonal when indicating a position with the cursor.
Or use EO, EH or EV for that matter, active until EN.
While selecting the Alt key lets you choose from stacked entities if any.
Holding down Ctrl or Shift in combination with the mouse wheel pans in one direction.
Pushing on the wheel pans freely.
But this still eludes me:
And those CAD programs then guess the direction or must you enter that too by keying in an angle.DabblingSeer wrote: ↑Sat Sep 06, 2025 3:54 ammany CAD programs let you type the exact length as you draw.
Sounds like a relative polar coordinate to me.
Regards,
CVH
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Re: Feature Suggestion: Dynamic Measurement Input for Lines
CVH Your help was huge. I thought I had to hit ctrl + Alt everytime I want to input a number, butt I don't. This is exactly how I wanted it to behave it's dynamic. I figured out the alt before to constrain it to 90°, EO also does it. I will go through all the tutorials as this is one bit of software I truly enjoy using.