Problems with exact metrical modelling

Hello everyone,

I am rather a noob with regards to Blender, but I have a solid background in 3D graphics and visualisation. I am stuck with a problem I have when I am trying to model a tile asset based on a cube with an additional extrusion. The problem I am facing is that my base cube has the dimensions 4m x 4m x 0.1m . Based on this I am doing a loop cut to seperate a part of the cube with a width of 0.5m. This part should then be extruded for a room height of 3m, so I am pressing “e” for extrude and enter “3” (for 3 meters) for the extrusion amount. The result can be seen in the attached screenshot, which shows me a horizontal edge length of 120m along the extruded edges. This also has effects on my later UV-unwrapping where the faces along the extrusion direction are strechted extremely compared to the other faces of my tile.



My question is: How can I correctly model the tile from my screenshot, so that I get correct metrical edge lengths afterwards?

Thanks in advance,
Thoran

Hi Thoran,

try again with scaling things in edit mode. If you scale the base cube down in object mode without pressing > control A > scale which means applying the real scale to the mesh it does not give you the results you need for extrusion in edit mode.
In other words scale the cube down to your needed scale in object mode and apply scale. Or do it in edit mode without the need of applying the scale thing. You can find it also in menue > object. Now it should work when you enter values for extrusion in edit mode…

Did you scaled or rotated your object in Object mode at any point of your modelling ?

In that case it could be the reason press E then 3 on that face do not result in 3 meters, so in -Object mode- before making your extrusion select your object and press CTRL+A -> Rotation and Scale to apply them.

Unapplied Object Mode rotation and scale will impact the modelling tools in Edit Mode.
Note : rotation&scale done in -Edit mode- do not need to be applied.

edit : Piet was faster.

sorry Sanctuary :slight_smile:

Thanks for your replies. In fact I was just creating a cube with “Shift+A” and specifying its dimensions, where I entered a radius of 2m. Then I scaled the cube along the Z-axis to 0.1m. Obviously this seems to be responsible for my “stretched” edge lengths in edit mode. I will give the applying of the scaling in object mode a try and see if I can get it working.

Actually I created a cube using “Shift+A” in a new scene. I specified 2m as radius for the cube and the scaled it down along the z-axis to 0.1m height. Obviously this seems to be the cause with the scaling not being applied. I will give it a try and see if I can get it working.

On a second thought, I realized that I actually adjusted the cube using its dimensions as you can see on my attached screen. Do I have to apply dimensions too? The scaling factors for each axis are all 1.0 so I guess applying the scale will not really help.



Probably I have to do all my scaling in edit mode and leave the object unaffected in object mode.

Thansk again,

Thoran

It’s okay to do some scaling in object, as long as you apply the scale :smiley:

Also, another tip is that if you go to the Scene Properties panel (the third one that’s between the “two pictures” – or render layers – and the world properties), you can select the metric units. Then, when you go to move a vertex, edge, or face in edit mode, you can simply hit 3m (or cm, mm, km, etc.) to move it precisely 3 meters. (Also works with imperial units too… inches, feet, yards, etc.)

Thanks for your reply. In fact I am using the metric unit setting, I just forgot to set it for the quick scene setup I did for creating the screenshot :slight_smile:
I did apply the scale with “CTRL+A” as Piet and Sanctuary pointed out. But I expected the dimensions to be cleared to (1,1,1). Maybe that was just a wrong assumption.

Thoran

The scale clears to 1/1/1, the dimensions (= the look of the mesh) stay the same. That’s the beauty of the Ctrl+A command!

Thanks for all your replies. With the usage of “CTRL+A” my extrude works correct and the UV-unwrapping afterwards also seems to be ok.

Thoran