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So this is a bit of a "hard to formulate a title for" question, but the thing is, i have two mesh objects. Both of them sit at the same position in Z when i select them in object mode and look at the item panel where it says transform: location. both have 0.11mm as z value, and the bright orange point (i think this is the origin of their respective local coordinate systems) for both f them sits at the same height, although not in the same spot on the XY plane.

both are simple meshes, a bezier curve converted to mesh and extruded in z axis to get a row of polygons. Now, for the first mesh i get a local value for the height of the extruded part which is 2mm. For the second mesh, i get 0,614. Although they are actually the same size visually (also in orthographic view). Im really confused, and the only thing i could possibly think of playing a role here is that the objects have been scaled beforehand and now are coming from different scale points of reference.

I have worked with a lot of modeling tools so far, tbh not with C4D, as an example, when it was important to have precise measurements. But all of them had local and global coordinates, but not local and global scale, if that even exists in this case.

So i guess my question is, where can I read how this differentiation in scale works in blender, and maybe a method of setting the local scale (if it exists) to the same value for two objects, so that i can have same local sizes for both of them.

Edit: here is a screenshotEdge Length Difference The explanation in the suggested thread by @gordon brinkman is exactly what i was missing. I dont understand whats going on completely tbh but enough to be able to work around it, so thank you to all of you.

ozr2222
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  • Hi :). I feel like you're perhaps confused about the Scale/Dimension values relationship? Would you please add a simple screenshot to illustrate which values you're talking about? – jachym michal Aug 31 '22 at 16:59
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    Does this answer your question? the measurement in blender is weird. I guess my answer there might help with the understanding of scale and dimension and different size though seemingly the same etc. – Gordon Brinkmann Aug 31 '22 at 17:02
  • If it's not a TL;DR, maybe this will help – Robin Betts Aug 31 '22 at 17:11
  • It sounds to me like you’ve conceived everything correctly. I’ll try to bring up the specific article in the Blender manual… https://docs.blender.org/manual – TheLabCat Aug 31 '22 at 23:52
  • I could not find a specific page in the manual that covers this, but you should look at the Object tab in the Properties editor. Also, you can press N in the 3-D view port to show the properties side bar, and check the Item tab. Either one will show you the object’s scale. – TheLabCat Aug 31 '22 at 23:55
  • @GordonBrinkmann this is exactly what i was missing, thank you for the in detail explanation. It still seems to be a very weird approach. does this have to do with you also not really beeing able to scale edges on a number input base? it seems like blender doesnt like to deal in absolutes ^^ – ozr2222 Sep 01 '22 at 10:03
  • @ozr2222 You can enter numbers when scaling edges... or do you mean scaling a specific distance in meters? That's not scaling. In geometry, scaling a vector (and vertex locations etc. are vectors) is multiplying the vector with a scale factor, this factor you can enter when scaling. You can either scale uniformly or, if you restrict it to certain axes, this works like an entrywise multiplication or Hadamard product with one or more axes multiplied by 0. If you want to reach a certain distance you must either know the factor between old and new length or move one or more vertices. – Gordon Brinkmann Sep 01 '22 at 10:40
  • @GordonBrinkmann yes youre right... i cant verify with other modeling software right now but i think i can remember that you can only scale it by a factor, not enter an actual size when scaling. – ozr2222 Sep 01 '22 at 11:43
  • @ozr2222 No, because scaling is not necessarily for a single edge, face etc. And if you wanted to "scale" two edges of different lengths pointing in different directions by 2 meters, which one of them should be scaled those 2 meters? And if you say both but they have diffferent lengths, then the factor would be different for each which means it would no longer be a vector scaling. – Gordon Brinkmann Sep 01 '22 at 12:00
  • @GordonBrinkmann i mean you can either scale the edge along its orientation, or scale it along another axis, like the global coordinate system. along its orientation you can only scale one edge (or mutiple one along their respective orientations at the same time), but according to a coordinate system you can scale as many as you want. but its ok im not very good at using the appropriate terms and i think i understand you. – ozr2222 Sep 01 '22 at 13:01
  • @ozr2222 Yes, of course you can scale in many orientations and coordinate systems - but it's always scaling by a factor. Not by a certain amount of meters. – Gordon Brinkmann Sep 01 '22 at 13:22
  • @GordonBrinkmann ok sorry i think now i got it, yes that was not precise from me - i meant scale to a certain amount of meters or units. not by meters thats just not possible right. but make it so that its x meters in x y or z – ozr2222 Sep 01 '22 at 18:46
  • @ozr2222 Well, if you know the dimensions you want that's easy... if something is 4 m in x and it should be 5 m, scale it by 5/4 = 1.25 on x axis ‍♂️ or if something is 3.14159... m in x and it should be exactly 5 m - just enter 5 m in its x dimension, then apply the scale with Ctrl+A – Gordon Brinkmann Sep 01 '22 at 19:07

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