[SOLVED] Precision import problem

[a.ershov]

There are some problems with importing model from 3ds max 2012 to unigine game sdk. In 3ds max I creating model using vertex snaps, and there isn't any gap or polygon overlay each other, vertexes have same coordinates in different parts of model. After import in unigine I see these shifts, some parts of model shifted by a couple of cm by z-axis. Export like a single model or like a different surfaces in one group have same error at unigine. Precision change to 10 has no effect.

[nat.harrold]

https://developer.unigine.com/forum/topic/132-insufficient-mesh-z-coordinate-precision/?hl=half+float#entry627

[nat.harrold]

Other things to check are:

 

Mesh pivot relationship.

 

mesh pivot that is centred in z will give better result - export from pivot.

If mesh is high in z in 3d package (even 20 or 30m) and world export is used then degraded accuracy on z axis will be evident.

[a.ershov]

I manually set all pivot points in 3ds max at (0,0,0) , export with world align - same result as first screenshoot, same z-shifts. Pivot align in export gives normally z align of surfaces in unigine, but some surfaces rotates in xy plane and I can't rotate them without rotating all mesh. So manipulations with different pivot aligns in 3ds max give no result.

 

 Also I try import mesh like a dynamic mesh, it solve z shift problem, vertex have them original positions. But I need import 2+ millions polygons into scene for enviropment, and use dynamic mesh not suitable for this. 

 

As stated in the above post, we enable render_use_vertex_float but this also doesn't give the desired result

[sebastianbah]

Hello Andrey,

It would be heplful if you can provide us 3Ds max model as a test-scene so we can give you more specific information about this issue.

Thanks!

[a.ershov]

This is an element that I try to import in unigine, 2012 max.

 

column_part.rar

[werner.poetzelberger]

Hello, 

 

just played around a bit.

 

I exported the model and have the same gaps as you described.

 

Then I exported the model with a scale factor of  0.01 and scaled it up in Unigine by 100 (the node) and the gaps are gone.

 

Cheers

 

Werner

[a.ershov]

Werner, thanks for idea, yes scale solves some problems, but we can't use it due to the fact that physics doesn't work correctly with the modified scale in the engine. We need scale factor = 1 for all meshes in unigine for our scene.

[sebastianbah]

Hello Andrey,

If it's suitable for you, you can use Align: Center in 3Ds Max Exporter in this case to improve the precision.

The closer the point to the zero point, the better it is calculated.

[werner.poetzelberger]

... hmm. Then you probably need to model it differently.?

[a.ershov]

As I say before, export from (0,0,0) coordinates in 3ds max with center alignment (or other variants, I try all possible in exporter) gives same result... 

Also I was try to divide model in different meshes in max and export it apart but it wasn't help. Anyway in this scene we need many surfaces, or meshes with different materials and textures which will be docked by vertices with 100% precision like in 3ds max. In previous scene I don't have this problem with similar models and same scale and size.

[nat.harrold]

What is the real world / physical size of your model attached above supposed to be?

 

approximately 14 metres high?

 

It works fine for me, if:

 

I get max's system and file units to metres

correct the models size in max

reset xforms

export with scale 1.0 - pivot is still at the origin

import to unigine. all surfaces match.

 

 

-your scene is in millimetres (model is approximately 140mm high), when you export mesh out at scale 1.0, the model in unigine will be huge, as each unit in max is treated as one unit in unigine. you may be exposing some non visible errors within max or within max to unigine translation.

 

Hope this helps.

N.

[andrey.ershov]

We use this scale to avoid problem with animations, and upscale static geometry in unigine make some problems with collisions. 

 

I resize all static geometry in 3ds max on x0,1 with reset X-form, and in export use scale=10 to take same size in unigine with scale=1. Model is ok, like in 3ds max.

 

Problem solved, thx all for help.