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Define Measurement Units and Edit Scene Scale


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Hey everyone...

As I did not have much knowledge with 3d-coat in relation to Define Measurement Units and Edit Scene Scale.
I started a project without paying attention to these two important settings that are found in the Geometry menu.

I would like to ask the help of all of you to used this topic to explain the subject better and with that you would help others who use 3D-Coat.

Doubt 1)
In a project I'm working on, only now that I've realized that the values in the Edit Scene Scale are all changed as you can see in the image I've attached.

If I change the value of SceneScale to 1 will what happens in my file? I would have problems if I change this value which is currently 137.963562 for 1?
Could I change units from millimeters to meters? Because it is in millimeters...

Could someone explain it better?

Doubt 2)
I realized that by default 3D-Coat uses millimeters.
I would like to have a 1: 1 ratio between 3D-Coat and Blender because of a 3d print job and I also believe it will help in mesh workflow for animation and games.

Currently in 3d-coat version 4.8.21, what would be the best configuration between 3d-coat and blender without there being any problems in the scale and positioning when it imports -> exports -> imports again for 3D-Coat?
I realized that when I use these 2 programs, the scale almost always changes. Maybe because I do not know how to configure.
Sometimes the sculpture when it returns to the 3d-coat comes either large or small and the pivot gets altered also causing the sculpture to be located in another position completely different from when I exported.

I think using meters would be the best unit of measure because I've read that physical simulations, displacement maps and other things will be best produced when configured using actual measurements of the world in meters.

How do you work with Measurement Units and How does the Edit Scene Scale work?

Doubt 3)
How to properly set up each project (for 3D print? for Games? for animation?) What would you advise for 3d-coat users in the initial scene setup within 3d-coat?

Anyone who is knowledgeable in this subject, please share with the whole community about all of these subjects that I mentioned above. This is very important...

Thank you for your attention and help.

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I don't know I've tried following peoples instructions here, many times, but it never seems to work right.  I find the whole 3D Coat measurement and scale thing very opaque and arbitrary.  I end up scaling everything I import and export by hand.

I'm also using Blender.

Edited by Falconius
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@Falconius I did the same thing as you, but I did not have much success.
Actually, I do not understand how to set the scene in 3D-Coat for specific projects like I mentioned in the topic introduction.

If a 3d-coat user wants to work on different kinds of projects how could he set the scene of it ?!
Because there are projects aimed at:

1- 3d printing: We have to be precise in the measurement units (priority for meters or centimeters). Where there must be an exact 1: 1 relationship between 3d-coat and the blender, otherwise we will have problems.

2- Animation-oriented project: Please correct me if I'm saying something wrong ... But as I said we need to use real-world measures to succeed, because there might be some kind of problem with respect to simulations of physics, displacement map and other things. I say this because I've seen and read several people commenting on that kind of subject.

3- Project focused on games: I will specifically talk about Unreal because I have an interest in learning this engine. I think for Unreal the ratio of units of measurements should be in meters and need the exact ratio of 1: 1 to avoid problems.

In my current project, you can see that in SceneScale, something happened to be left with strange values. I think the default is X, Y, Z = 0 and SceneScale = 1.
I do not know what happened. It may have been some export process -> import that I did and I did not know that would happen that kind of behavior inside the 3d-coat.

I do not know how much the SceneScale and units of measures influence the design within the 3d-coat. I do not know if these values influence Voxels, surface mode, brushes and 3d-coat functionalities.
I think it must influence in some way ... but I confess that I do not know.

I created this topic so that us 3d-coat users could clarify and understand this subject that is very important in the accomplishment of any project.

Please, anyone who has experience and knows about it, share it with everyone so that everyone can correctly configure the project within 3d-coat and with other applications.
Thank you very much.

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  • 5 months later...
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I agree 3DC scale is a little confusing. 

My testing from a number of  years ago and the below is helping in the best way I can.

The below covers the Sculpt room.

Scene scale is in units.  Units is really undefined to the user except that the default "1" is quite large in real world measurements. 

Increasing the number will make the scene scale smaller in real world measurements.

A setting of 100 scene scale and set to meters will import Blender models with a 1 to 1 ratio. The default 2 meter Blender cube will import into 3DC as a 2 meter cube. Also when exporting from 3DC, the importing of the model into Blender will be correct. 

When creating your model in 3DC the same holds true, have your scene scale set to 100 plus set to meters.

I recommend creating different 3DC files based upon the projects you need. You can load those depending your modeling project.

Save the project with a different file name , keeping your base 3DC file for future use.


Some background information.

Before surface mode we only had voxels, you had to scale up to get enough voxel resolution for your models. That is the reason for the import dialog box when it ask you too keep the scale of the original model upon export.  Though you scale up the model for resolution sake, when you export, the original scale is kept. No change of scale in your model


Importing directly into a paint room that is empty will change your scale no matter what the original scale is set at. 

 3DC automatically either reduces the scale or makes it larger so you model  fits in the viewport for painting. This does not change the scale of your model when exporting. 3DC also centers your model in 3D space.  This will again not effect the exporting of the modlel but is only an internal feature of 3DC. You can tell 3DC  not to center the model in viewport but keep it location in 3D Space in the import dialog box. 

Now this was fine before we could transfer the paint model to the sculpt room for tweaking. I have to test if this effects the exporting from the paint room after tweaking the model in the sculpt room and then exporting from the paint room. I been away from 3DC for several months as family health problems called me away so no testing done.

What we need is the ability to tell 3DC to load a model into the paint room without changing the scale of the scene we have already set plus load the model into the current paint room scene. I have a workaround that might work but need to test it so you can keep your current scene and scale.

Right now if I have the Blender scale scene open and I directly import the model into a empty paint room, the paint room having no current object in it, 3DC creates a new scene and scales the model to fit in the viewport.  If I get enough time I will send Andrew a few ideas on this in e-mail.

Hope the above helps some. Here is a basic 3DC Blender scale scene.  Test it and post any problems you have.

Scene scale set to 100

all axis set at 0,0,0

Meters set.

This is a good topic and worth exploring in more detail in a constructive manner. Remember the above is only information I gained not a end all or that problems do not arise.






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More information.

If you change the scene scale after directly importing into the paint room, It adversely effects the brushes. The diameter of the brush is no longer correct.

Ok, I got a workaround for keeping the current scene and scale when importing a model in directly into the paint room. It is not pretty but works. We stiil need the ability though still to keep scale when importing into an empty paint room scene plus keeping the current scene, not creating a new one.

My file is set up to match Blender's scale.

The scene.

scale set a 100, all axis set at 0,0,0 plus set to meters

I have a holder cube in the paint room for per pixel paintiing. 

Use only " Import object " under the file menu in the paint room to import your Blender model into the paint room without changing the scene scale. This will import another model into the scene without changing the scale.

Do not use (Import) under the file menu.

Once you load your Blender model , you may delete the holder cube and it's surface material.

Now the above is only a way I found that works and not tested in-depth at all. You are welcome to try it.


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I would like to express my thanks to you @digman .
Thank you very much for sharing your knowledge and experience on the subject of the topic.
Honestly, I had even forgotten that I had created this topic because I did not have answers to the doubts regarding the different types of projects in which the configuration of the Scale correctly has direct importance in the completion of a project.

As soon as I can, I will conduct tests and share my experiences on the subject as well.

I had already thought about creating a saved scene with specific settings for a given project. Thanks for mentioning this.

And once again thank you very much for sharing with us this valuable information by enriching the content of the topic.

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1 hour ago, Carlosan said:

What do you suggest as a change to make it more user-friendly ? 

Hi @Carlosan Thanks for asking....
 For this,
to make more user-friendly , I had already thought of something that could make life much easier for the user of 3D-Coat.

I would like to suggest that we could have an initial Project window (similar to a new Krita document window or GIMP or Photoshop).
In this Project window, the user could define all possible configurations or specifics (these settings could be suggested by the users so that the 3D-Coat team could select which ones would be present) for his or her specific project and then save this Custom setting.
Or the user could choose pre-defined project settings in 3D-Coat.

It could have project presets such as: (According to the preset chosen the Scale would be different according to the workflow, along with the other necessary configurations.)
- 3D printing
- Games: Unreal, Unity and etc
- Animations (Here I refer to projects aimed at films and etc)

Below is a quick picture so you can understand what I'm talking about.


Of course this idea is very crude, but it could be very refined and blended with the initial 3D-Coat window.

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I believe that simplicity is the key to continue, to make difficult things simple to perform.

Digman was very generous sharing this information, but imagine if I have to explain this wall of text to a new user ?

Do you have to take all these variables into account in order to do your job well ?

It does not seem to be the path of an artist but of a scientist.

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Paint room importing to keep scale. The paint room is empty, no model in this case.

1. We already have the ability to add a model into the paint room once a model is already there and the scale is not changed.


New Feature.

 I would suggest adding to the import dialog menu the ability to import a model as an option when the paint room is empty into a saved scene with scale set or a scene we have created the scale for. The scale will not be changed nor the measurement units.

Atm, 3DC creates a new scene when importing into the paint room (empty room )and you lose your scale settings.

The above would be easy to show and explain to a new user. 


As far as setting scale in the Sculpt room for a specific project, that I think comes through just using the software for awhile.

Only by testing did I find out that 100 3DC scale units equals Blenders meter scale when the scale is set to meters in 3DC. 

The above can be told a new user, increasing the scale upwards till it matches your other software scale whatever it is. 


New Feature.

There could be some presets files that are already set for different software  scale.  Raggard suggested this...

In the New menu,  Drop down list could be added to various ways of importing, You could select a preset file with the correct scale for that software. This is similar to what we can do for normal maps in selecting a preset. This would make it easy for a new user.

The community could get involved here as well, creating preset files and sending them to the development team to be added to the list.

The above are suggestions and open to discussion.

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Of course, all of the things that were suggested could be refined and we would have something very polished and simple so that a more experienced artist or new user of the program can use 3D-Coat in a simple, fluid and intuitive way.

In my opinion, the ideas of presets with settings is very good and simple to understand and use.

I believe that most of the artists use programs like Photoshop, Gimp, Krita and etc. We all know that we have to change the document size, dpi, depth bit and other settings according to the project that will be created.
As well as, we also know that we can save a new preset according to our choices and then use it again and also we have presets already defined with the most used project configurations in the market that we can choose.

A simple example that happens to me (related to a specific configuration):
When I open my project in 3D-Coat, I have to click the Rotation Mode button every time to work in Free Rotation mode, because 3D-Coat does not remember the configuration that was chosen by me.
Of course this was a simple example and it has nothing to do with Scale, but it would be great if users could set initial settings for a new project according to the needs and the project it will work on.

If you are a new user with no experience whatsoever, he could choose a preset according to your needs and if you need to change some settings of this preset he could.

Imagine, a project related to 3D printing.
There could be a preset called 3D Printing, with several settings directed towards this goal.
Example of one of the preset settings:
- Workflow of used programs: 3d-coat to Blender (the scale would be defined for the use of the 2 programs). With this, using 3d-coat to blender -> Blender to 3D-Coat would be a fluid process and no scale changes or problems.
Just as there would be other configurations for this particular project.

As Digman said, the community could share its presets and with that we could increase the compatibility of various external programs with 3D-Coat. This way, we would have a correct and smooth workflow between different types of programs.

I think simpler than that would be impossible!
The person would not even have to think about choosing a particular preset and would not even need to make calculations and mathematical formulas thinking about the program workflow, as well as what unit of measure the user would use and so on.

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The complexity of "scene units" "scene scale" "grid size" "voxel per units" are, really troubles me with use "measure ment" tools.

If I make something from scratch in 3d coat it not matter. but when I need to make morph with texture, for character  which made in blender,or use character which used another aprications,  or game mod, and need to work often between 2 aprication, I really hope to keep simple and stable work-flow.  and hope to get one official clear document for import -export with keep scale in  all work room. (paint, retopo, sculpt) with measure ment tool, but set voxel density as we like.

In principle , import ,export with  keep size for each aprication  is not difficult .  it is actually simple math.

eg, daz studio use 1cm for "scene units". then in blender. most of user may prefer 1m.   to make morph etc. then I export obj from daz studio,  use "0.01" (1%) . then it fit about aprication which use scene units = 1m.   I export obj from blender keep default (1.00), then when import it to daz studio, I adjust import scale setting use "x100"  ("10000" %).

  but I can not still find good work-flow about 3d coat. I reall hope to get preset and hope to make custom one , but untill thinking about preset, 3d coat need to  keep "scene units" for all room and all new scene, untill user change. Of course we need to change grid-count ,grid-density,  voxel density, measurement-units as we like without change scene unit. (cm , mm, m / per 1 unit)

I really thanks digman offer many answer about this problem, but I still feel it not work with measure ment tools. and when user try to change grid ,and voxel density.  or I miss something still.  If some one know about 3d coat scene units, and measure ment tools,  follow this simple example please.

1 make simple rectanglar.  in blender. x = 1m,  y = 1m, z = 2m.   with use blender scene units = 1m.


2  import it to 3d coat "paint room" .and use measurement tools ,show  same number (in 3d coat, x =1m, y=2m, z=1m for world cordinate) from frot view.

3  show 3d coat grids as same as blender unit ( 1m) 

4a  tweak only one vertices, in shape(tweak)  room, then export it as new shape key in blender.

4b from paint room,   import it to voxel room obj, with surface mode, then use pose, or transform tool, with auto-fit retopo mesh.

 then export modified "retopo mesh "as morph (blender shape-key)

what settings you can use?  could you do it easy?  and you could still free adjust grid density, voxel density as you like?   as you know these steps should be done without many tweaking. we may only need to setting correctly, and suppose the setting should work untill we change something. but about 3d coat it not work as I expected,,, 



Edited by tokikake
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And I do not know what "voxel per units" means. 

I suppose it simply decide when we import mesh as voxle, it auto-generate the voxels of number which I decided.

In this case I keep Units as "Meters", and Voxels per unit (aproximately) = 1000 


I suppose, if I add new obj in sculpt room, 3d coat auto-generate 1000voxles per meter. it is enough for me to keep primitive shape.

  but when I import primitive from vox stamp, (which 3d coat offered), or use primitive tool, then add new mesh as voxel,  and adjust scale, to fit current scene unit and size,  (almost 1m diameter, compared with another mesh)  after all it just generate mesh without  1000 voxels   then  it can not keep shape. 


of course I know, I may only need to adjust layer density, but  voxel per units not work ? 

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Another 3DC user pointed me to an earlier version of 3DC that still has the Scale command under the File, Import Mesh for Voxelization.

Even though this version is 4.8.10, I find it does exactly what I need on this scaling on  import issue.    I understand this capability still exists with later versions, but is only available with the gumball-type tools (sorry if wrong nomenclature).   I never learned how to work that "gumball," as I only use 3DC for a few things.


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  • 3 months later...
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OK now i am more confuse with the units system in 3d coat since i recently start working with 3d coat and i need a solid scale import/export from blender to 3d coat.

What i need to know is what unit should i set 3d coat to match blender in cm? My guess is 1000 but i am not sure yet.

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  • 3 weeks later...
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4 hours ago, haikalle said:

I have been taking a look at this issue. I have found out that for example if you import mesh into ppp it will change SceneScale number. Is this wanted behaviour or not?

I found the same thing when I looked a measurements in 3DC last year.  I think 3DC is changing the scale so the model is large enough to fit in the viewport  for painting purposes. The scale could be increased or decreased depending upon the scale of the object. 3DC remembers the original scale upon export from the PPP room. That is my quess but it is only a quess  for changing the scale upon importing into the PPP room.

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Thanks digman. Your feedback is always very informative. I think you right. I have access to 3d-coat code and it seams that it's using the size of the mesh to calculate the SceneScale. I think haven't seen this 
kind of parameter in other 3d app so it really needs some thinking to understand it fully.

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3 hours ago, digman said:

3DC scene scale set to 100 / Units set to meters will match the metric scale in Blender. This  setting I have been using for years.

3DC scene scale of a 1000 / units set CM should be ok for Blender as well. I did a quick test and it appears to be correct.

Of course you have to setup Blender to use Metric and not Blender units.

Thank Digman that was a few week ago now i understand the scale between both programs.


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  • Carlosan changed the title to Define Measurement Units and Edit Scene Scale
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  • 1 year later...
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What's the current situation of "Importing to Paint Room without changing the scale"?

It has been like, 4 years. Surely 3Dcoat has fixed it?

The auto-scale-to-viewport is an anti-feature that shouldn't have existed from the beginning.

Edited by Kodra
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  • 2 months later...

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