# How to make a perfectly flat bottom for 3D-printing topographic relief?

I'm trying to print a topographic relief, I'm close to the end but I can't find a way to have the back of my object perfectly flat without changing the top.
(I tried to SY 0. didn't worked)

• why not just select all the vertices on the bottom and scale along the Z to 0? – X-27 is done with the network Apr 26 '15 at 23:58
• can you show the wireframe, and how is it generated , does it have modifiers ? – Chebhou Apr 27 '15 at 0:00
• I think this is using the solidify modifier, so you will have to create a bottom first than flat it out ( looking at the Rim) – Chebhou Apr 27 '15 at 0:02
• @SelmaB please write the solution as an answer and accepted so this get closed – Chebhou Apr 27 '15 at 0:33
• @Chebhou Don't say closed, sonds like we are going to close it as off-topic :P But yes @ selmaB, post an answer. The site's stats are negatively affected otherwise :) – VRM Apr 27 '15 at 1:11

The solidify modifier can be removed, if you need to do this kind of thing a few times do this instead:

• Select your Mesh, go to Edit Mode, Select All geometry.
• Hit E to Extrude, Then Z followed by Z again to constrain the direction
• Then move the mouse to the right, and the newly extruded geometry will start to move down. You can see by exactly how much in the bottom left (by default the contrast between the text and the panel make this unnecessarily hard to read (April 2015). But it looks like this

You can use the mouse, or left / right keys, or even type the number you want directly with the num keys.

• then to flatten the new geometry, hit S, Z, follwed by number 0.

Here's a view from the underneath before and after the flatten.

### Cons:

there are all kinds of factors that can interfere with how straightford this is, the location of the reliefs Object origin being one of them. If I had to do this repeatedly, it would be something to write a small python script for.

The recipe for such a script might be:

• find lowest z coordinate of the original mesh
• extrude all faces a little bit
• replace all z values of the newly geometry with the lowest z of the original mesh minus the desired thickness.

This would produce a mesh with a minimum thickness.

In case you are using the solidify modifier :

• create two materials in the material tab :

• change the material index offset to 1 as follows :

• apply the modifier ( click apply button in the above image )
• in edit mode hit A to deselect all the vertices ( nothing is selected now)
• in the material tab select the second material and click Select (the first image )

• All bottom vertices are selected now hit S then Z and last 0

Select bottom vertices, press S > Z > 0.

• This site is in English so please write in it. Note also that more in-depth answers were already added long ago and there's no reason to add less detailed. You might want to take a look at tour page to see how this site works. – Mr Zak May 3 '19 at 21:06