<p>This answer assumes you're working in the Part Design workbench.</p>
<p>So you want to adjust the starting height of a pad or pocket. There are two ways I can think of to do this easily.</p>
<ol>
<li>Adjust the Z attachment value of the sketch to lower the sketch below the surface.</li>
<li>Use the &quot;two dimensions&quot; option in the pad/pocket operation and set the second value negative.</li>
</ol>
<p>By the way, it is highly suggested not to attach a sketch to a surface. The current development version (0.19) and previous versions have an issue (<a href="https://wiki.freecadweb.org/Topological_naming_problem" rel="nofollow noreferrer">&quot;topographical naming&quot;</a>) where editing a previous feature can change the internal name of a face causing the attachment to break. There is a solution under development but it doesn't loom like it will get in earlier than 0.20. You should instead simply adjust the Z attachment value to match the face you want.</p>
<p>Also, there is a very active (and very helpful) forum <a href="https://forum.freecadweb.org/" rel="nofollow noreferrer">here</a>. I'd suggest asking further FreeCAD questions there.</p>

CC BY-SA 4.0
2020-10-11T04:18:25.237Z
Thanks, really helpful. Very much a beginner, didn't realise one can jus create a new sketch without attaching it to s face. I have noticed strange happenings when I've gone back to make changes, so maybe I have seen this issue. I'll try the forum.
nmw01223
CC BY-SA 4.0
2020-10-09T21:09:36.807Z
2020-10-09T21:09:36.807Z
DoxyLover
<p>I am a raw beginner at FreeCAD and 3D draughting. Watched some tutorials and designed 2-3 simple items. Aiming to use it for 3D printing.</p>
<p>My question relates to 2D sketching. As I understand the workflow, one draws 2D items that one can then extrude, cut etc. So one picks the drawing axes (eg X and Y), and the sketch is then at Z axis zero. After extruding, one can place another sketch on a face for further extruding etc.</p>
<p>But the sketch is always at relative Z/3<sup>rd</sup> axis zero.</p>
<p>Consider a fairly large block extruded 10 mm thick. Say I want (example only, never mind  why) to cut a 20 mm disk from the interior, 3 mm deep, 5 mm from the bottom surface therefore 2 mm from the top.</p>
<p>If I place a sketch on the top surface, make a 20 mm circle and use that to cut a hole, the cut will always start at the top surface - but I want it to start 2 mm down. I.e. it seems to me I need to be able to offset the sketch from local Z/3<sup>rd</sup> axis zero, in this case to -2 mm.</p>
<p>Can one do that, or have I missed the point somewhere?</p>

CC BY-SA 4.0
2020-10-09T20:47:15.150Z
so you want to set an offset of -2... Do you use StekchUp or FreeCAD?
Trish
CC BY-SA 4.0
2020-10-11T04:17:04.823Z
FreeCAD, but maybe the answer below is what I need, thanks.
nmw01223
<freecad><sketchup>
Beginner FreeCAD question on axes when sketching
nmw01223
# Beginner FreeCAD question on axes when sketching

(Asked by: username_0 on 2020-10-09)

I am a raw beginner at FreeCAD and 3D draughting. Watched some tutorials and designed 2-3 simple items. Aiming to use it for 3D printing.

My question relates to 2D sketching. As I understand the workflow, one draws 2D items that one can then extrude, cut etc. So one picks the drawing axes (eg X and Y), and the sketch is then at Z axis zero. After extruding, one can place another sketch on a face for further extruding etc.

But the sketch is always at relative Z/3rd axis zero.

Consider a fairly large block extruded 10 mm thick. Say I want (example only, never mind why) to cut a 20 mm disk from the interior, 3 mm deep, 5 mm from the bottom surface therefore 2 mm from the top.

If I place a sketch on the top surface, make a 20 mm circle and use that to cut a hole, the cut will always start at the top surface - but I want it to start 2 mm down. I.e. it seems to me I need to be able to offset the sketch from local Z/3rd axis zero, in this case to -2 mm.

Can one do that, or have I missed the point somewhere?

**Tags:** freecad, sketchup

> **Comments:**
> **username_1**: so you want to set an offset of -2... Do you use StekchUp or FreeCAD?  
> **username_0**: FreeCAD, but maybe the answer below is what I need, thanks.  

---

## 1 answers

### Answer by username_2 on 2020-10-09. Score: 1

This answer assumes you're working in the Part Design workbench.

So you want to adjust the starting height of a pad or pocket. There are two ways I can think of to do this easily.

1. Adjust the Z attachment value of the sketch to lower the sketch below the surface.
2. Use the "two dimensions" option in the pad/pocket operation and set the second value negative.

By the way, it is highly suggested not to attach a sketch to a surface. The current development version (0.19) and previous versions have an issue (["topographical naming"](https://wiki.freecadweb.org/Topological_naming_problem)) where editing a previous feature can change the internal name of a face causing the attachment to break. There is a solution under development but it doesn't loom like it will get in earlier than 0.20. You should instead simply adjust the Z attachment value to match the face you want.

Also, there is a very active (and very helpful) forum [here](https://forum.freecadweb.org/). I'd suggest asking further FreeCAD questions there.

> **Comments:**
> **username_0**: Thanks, really helpful. Very much a beginner, didn't realise one can jus create a new sketch without attaching it to s face. I have noticed strange happenings when I've gone back to make changes, so maybe I have seen this issue. I'll try the forum.  

---

