Help to fix Offset

martin bach

 Hello...

i am in the middel of making a roof in Bricscad, but when i try to offset a line 150mm, it never offset the line 150mm, it offsets the line 146/153/151/169/143 and so on it never offsets the line 150 like i want it to. 

what can i do to fix it? 

Roy Klein Gebbinck

It is highly unlikely that there is an issue with the _OFFSET command. It is important to realise that the _OFFSET command performs its operation in a 2D plane determined by the object. Perhaps you are working in 3D? When checking with the _DISTANCE command make sure to also pay attention to the Delta Z value.

Roy Klein Gebbinck

Naturally, I am assuming that you are using entity snaps when checking the offset results...

Roy Klein Gebbinck

... your OSNAPZ setting is also important.

martin bach

@Roy Klein Gebbinck:

Naturally, I am assuming that you are using entity snaps when checking the offset results...

i am using the template "default-mm.dwt" 

i use the tool "linear" to see what the distance is between the to parallel lines 

what should my OSNAPZ setting be? 

i haven't changed anything in my setting 

Roy Klein Gebbinck

Can you post a dwg with a dimension indicating where you think the distance is incorrect?

martin bach

 Yes here is a dwg with wrong offset. 

Drawing1.dwg

Roy Klein Gebbinck

Looking at your drawing I think there are two possible scenarios:
1.
You have entered '500' on the command line but the resulting offset is 498.069.
This would be a serious bug and you should report it to Bricsys.
2.
You pick points to determine the offset distance.
In that case I suspect there is a lack of accuracy on your part.
The fact that you have snap switched on and use 1 as the X and Y snap unit supports this scenario.

martin bach

@Roy Klein Gebbinck:

Looking at your drawing I think there are two possible scenarios:
1.
You have entered '500' on the command line but the resulting offset is 498.069.
This would be a serious bug and you should report it to Bricsys.
2.
You pick points to determine the offset distance.
In that case I suspect there is a lack of accuracy on your part.
The fact that you have snap switched on and use 1 as the X and Y snap unit supports this scenario.

So i should just switch off "snap". (i have tried that now and then the distance is 524 instead of 500 

what do you mean with "and use 1 as the X and Y snap unit supports this scenario." ? 

Roy Klein Gebbinck

First you should explain how you input the offset distance. Do you pick points or do you type a value.

Louis_Verdonck

Dear Martin

I cannot find any problem with the Offset command.I downloaded your drawing and did the following:

1. Launch the Offset command.

the command bar reads: Offset:  Through point/Erase/Layer/ <0>:

2. Type 500 in the command window and press enter.

the command bar reads: ENTER to stop/<Select entity>:

3. Select the line to offset.

the command bar reads: Both sides/: 

4. Click the side for the parallel copy

the offset is created at a distance of 500

martin bach

@Louis Verdonck:

Dear Martin

I cannot find any problem with the Offset command.I downloaded your drawing and did the following:

1. Launch the Offset command.

the command bar reads: Offset:  Through point/Erase/Layer/ <0>:

2. Type 500 in the command window and press enter.

the command bar reads: ENTER to stop/< Select entity>:

3. Select the line to offset.

the command bar reads: Both sides/ : 

4. Click the side for the parallel copy

the offset is created at a distance of 500

THANK YOU Louis, you just saved my day  

Jason Bourhill

@martin bach:

i use the tool "linear" to see what the distance is between the to parallel lines 

Sounds like you might also be using _DIMLINEAR (From the menu bar: Dimension > Linear) for measuring. This is for creating a dimension object that shows the horizontal or vertical distance between two selected points. i.e. it gives the distance in the X, or the distance in the Y direction between two points. It won't give you the total distance in the X & Y. For measuring suggest you instead use the _DIST command (From the menu bar: Tools > Inquiry > Distance) with the appropriate object snaps.

Regards,

Jason Bourhill

CAD Concepts 

Roy Klein Gebbinck

Just to clarify:
In my post #8 I have described two scenarios. The first scenario, obviously, was most unlikely: it was a foregone conclusion that the 2nd scenario must apply.
This brings the discussion to the importance of accuracy.
I have three tips for the OP:
1.
Read the 'Drawing Accurately' section in the Help.
2.
Change the 'Linear unit precision' (LUPREC) to 2 decimal places.
This will give you a better understanding of what you are doing.
3.
Switch off the SNAP or use larger snap unit values.
For architectural drawings where a drawing unit represents 1.0mm use 50 for the snap units. Or 10 if you are zoomed in on a detail. Note that this will lead to a 'jumpy' movement of the cursor. I rarely have the SNAP switched on. But it can be quite useful when 'sketching' out a schematic plan or for aligning texts and dimensions.