max to unity. unit sutup

ashraful mobin · Jan 2012

I am working on a project which will use unity and give the output for IOS 3. I have developed some assets using 3ds max 2012. I need to send the assets and animations to unity. I will rig the characters using biped. Now I need to know-
1. which unit setup I should use to export ? which will work in unity and IOS3.
2. should I use real world scale for the character and assets ? will it affect on game play. I mean will it make the game heavy ? after all its going to be a small device game.
thanks in advance for the repays !:)

gsokol · Jan 2012

Unity uses the metric system...so work in meters. And yea, You should work in real world scale. Lots of things depend on this....physics, light calculation, etc. Even if you may not be affected by those things, its a good habit to be in. Will it make the game heavy? Surely you don't think that the scale of the models is going to affect the size of the build?

Joseph Silverman · Jan 2012

Use FBX. I think with max and unity default settings 100 units from a max fbx = 1 in unity.

ashraful mobin · Jan 2012

thanks guys !

I really appreciate your help. I wonder if you guys could share some more information ! I am going to rig the characters with biped. I found that if I add some extra bone with default biped then the animation will be good. because my characters are little complex. how many bones can I use to run the game smoothly in IOS 3 ? is there any limitations ?( all the demos I have seen using less bones then default biped has) how does the bones effect on game run ?

gsokol · Jan 2012

Yea, basically having more bones on a character will increase performance hit, which is why the demos use less bones.

khepa · Feb 2012

for the mobile platform game, its better to keep the bones under 30 per character.

e-freak · Feb 2012

hijacking the thread a little bit: did anyone ever get rid of the fbx import scale 0.01 issue (every fbx gets imported hundred times smaller than intendend) and the axis conversion problem? (All Max fbx files display correct until you try to access the individual meshes within one fbx and they flip 90 degrees on the x axis)?

also:

is this the correct unit setup or would i set the system unit scale to centimeters as well?

khepa · Feb 2012

you need to change the Unit and axis conversion setup in the fbx exporter's Advance option. I think it will solve your problem.

e-freak · Feb 2012

Nope, that doesn't fix the Unity import issues. Unity entirely ignores the Up-Axis and the scale is always set to 0.01 when importing. The only "hack" would be to set the FBX exporter to scale up 100% and then have that reverted by the unity import, but it just feels wrong knowing that it has been up and down scaled before usage...

Target_Renegade · Feb 2012

One way I got round the axis' problem was to rotate the pivot point of the model in max so that it faced the right direction Up-Right, or something like that, it was a while back. Use the rotation tool on the pivot point and with some trial and error you should get there.

monster · Feb 2012

e-freak, if you want Unity to default to 1.0 you can do something like this:

Put a text file (javascript) in ...\Assets\Editor\ImportSettings.js (make the folder if needed.)

Paste this code into it and save it:

[COLOR="SeaGreen"]// This function will over write the default Unity import scale of 0.01.[/COLOR]
[COLOR="DarkOrange"]class [/COLOR]DefaultMaxSceneScale [COLOR="DarkOrange"]extends [/COLOR]AssetPostprocessor [COLOR="DarkOrange"]{[/COLOR]
	[COLOR="DarkOrange"]function [/COLOR]OnPreprocessModel [COLOR="DarkOrange"]() {
		if ([/COLOR]assetPath.Contains[COLOR="DarkOrange"]([/COLOR][COLOR="Yellow"]".max"[/COLOR][COLOR="DarkOrange"])) {
			var[/COLOR] modelImporter [COLOR="Red"]:[/COLOR] ModelImporter [COLOR="Red"]=[/COLOR] assetImporter[COLOR="DarkOrange"];[/COLOR]
			modelImporter.globalScale [COLOR="Red"]= 1.0[/COLOR][COLOR="DarkOrange"];[/COLOR]
		[COLOR="DarkOrange"]}
	}
}[/COLOR]

I haven't tested this, but I think it will work. You can remove the .max check if you want it to scale all models on import.

As for me, my unit setup in Max is 1 unit = 1 centimeter, and display is set to generic units. I've never had a scale problem. Nor have I experienced the axis problem you describe.

e-freak · Feb 2012

just found this, which seems to describe the problem pretty spot on. The scale fix looks like a good fix - thanks!

monster · Feb 2012

I guess we don't export as FBX we just let Unity import the max file. I know it does FBX conversion behind the scenes. But I've never selected something inside a prefab and had it flip on me.

I'll double check again, maybe my import script is correcting rotations. I created it such a long time ago I don't remember off the top of my head. I know I do other thing like remove reference objects.

max to unity. unit sutup

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