# Blender Object to ThreeJS (dimensions)

**URL:** <https://discourse.threejs.org/t/blender-object-to-threejs-dimensions/8039>\
**Category:** Questions\
**Created:** [June 11, 2019, 12:07pm UTC](https://discourse.threejs.org/t/blender-object-to-threejs-dimensions/8039 "2019-06-11T12:07:31Z")\
**Posts on this page:** 7\
**Page:** 1

<div class="post-metadata">

**Author:** ![y0un35](https://avatars.discourse-cdn.com/v4/letter/y/ecb155/32.png) [@y0un35](https://discourse.threejs.org/u/y0un35)\
**Post date:** [June 11, 2019, 12:07pm UTC](https://discourse.threejs.org/t/blender-object-to-threejs-dimensions/8039/1 "2019-06-11T12:07:31Z")

</div>

Hello everyone,  
I uploaded a blender 3D object (.obj & its materials .mtl).  
how can i set its dimensions via threejs?!also the units of measurements, can they be in pixelx if not, centimeters?  
thanks

---

<div class="post-metadata">

**Author:** ![looeee](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.threejs.org/looeee/32/59_2.png) [@looeee](https://discourse.threejs.org/u/looeee)\
**Post date:** [June 11, 2019, 12:12pm UTC](https://discourse.threejs.org/t/blender-object-to-threejs-dimensions/8039/2 "2019-06-11T12:12:00Z")

</div>

The three.js units are meters, by convention, and for lighting calculations if you have physically correct lights enabled.

However, that had nothing to do with the final width that things will be drawn on screen, which you can’t control.

More info here

> [@Units in Three.js](https://discourse.threejs.org/t/units-in-three-js/1174/):
>
> Hii, I want to create a line of 1 cm in THREE.Scene.I make a line by passing vertices value of {0,0,0} to {1,0,0} which makes straight horizontal line,But I have a doubt is it a 1 mm or 1 cm line ?? or is it measure in Pixel. Thanks & Regards Gaurav

---

<div class="post-metadata">

**Author:** ![y0un35](https://avatars.discourse-cdn.com/v4/letter/y/ecb155/32.png) [@y0un35](https://discourse.threejs.org/u/y0un35)\
**Post date:** [June 11, 2019, 12:24pm UTC](https://discourse.threejs.org/t/blender-object-to-threejs-dimensions/8039/3 "2019-06-11T12:24:19Z")

</div>

Thanks, yeah i already saw this post, but it didn’t help verymuch,!  
so there is no way i can get the exact width!!.  
because in my script the width of finger is 40px!.  
any idea?!

---

<div class="post-metadata">

**Author:** ![prisoner849](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.threejs.org/prisoner849/32/535_2.png) [@prisoner849](https://discourse.threejs.org/u/prisoner849)\
**Post date:** [June 11, 2019, 12:34pm UTC](https://discourse.threejs.org/t/blender-object-to-threejs-dimensions/8039/4 "2019-06-11T12:34:54Z")

</div>

Do you need to convert 3D coordinates to screen-space coordinates?

---

<div class="post-metadata">

**Author:** ![looeee](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.threejs.org/looeee/32/59_2.png) [@looeee](https://discourse.threejs.org/u/looeee)\
**Post date:** [June 11, 2019, 12:47pm UTC](https://discourse.threejs.org/t/blender-object-to-threejs-dimensions/8039/5 "2019-06-11T12:47:28Z")

</div>

> so there is no way i can get the exact width!!.

There’s no way to set a model so that it will be 1cm wide on every screen, because screens are all different shapes and sizes, and the pixels that make them up come in many different sizes too.

---

<div class="post-metadata">

**Author:** ![y0un35](https://avatars.discourse-cdn.com/v4/letter/y/ecb155/32.png) [@y0un35](https://discourse.threejs.org/u/y0un35)\
**Post date:** [June 11, 2019, 12:50pm UTC](https://discourse.threejs.org/t/blender-object-to-threejs-dimensions/8039/6 "2019-06-11T12:50:17Z")

</div>

Ooooh, so what do you think i should do?!  
the problem is: i want to build an app similar to this one: [https://www.youtube.com/watch?v=pPqTi-J6CgU](https://www.youtube.com/watch?v=pPqTi-J6CgU) except this one is a mobile app, and what i want is webapp.

---

<div class="post-metadata">

**Author:** ![looeee](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.threejs.org/looeee/32/59_2.png) [@looeee](https://discourse.threejs.org/u/looeee)\
**Post date:** [June 11, 2019, 1:40pm UTC](https://discourse.threejs.org/t/blender-object-to-threejs-dimensions/8039/7 "2019-06-11T13:40:45Z")

</div>

How are you planning to recognize what part of the photo is the part of a finger that the ring should go on?

Once you have that set up, you can measure how many pixels across the finger is and use that to calculate a size.