P3D v4 What export from MCX is not the same even the same material properties and texture.

[jtanabodee]

Hi,
My VTBS has been converted to PBR material by someone. I tried to study their work and I found many intereresting things. My project was done in Gmax. So I need to export in FSX.MDL. Then I use MCX to setup the same material and use their PBR texture. Then I export to be P3Dv4.4 by MCX. I place the new file with bglcomp.exe from p3dv4.4 sdk. When I look up in the sim, the lines are different desprite of all the same material setting and the same texture. Please take a look. The darker one is mine , the lighter theirs. In MCX show correct Normal. What did I miss? Something wrong with MCX regarding PBR material?

 

[arno]

Hi,

Without seeing the files it is hard to see. I would double check the normals and maybe there is one material attribute that is slightly different.

 

[jtanabodee]

I will upload the bgl files. You got the one that I told you in PM already. The file name is GroundWork.bgl.
Here is mine.

 

[jtanabodee]

I did the other way around. I loaded up their work in MCX and export as it is, nothing change at all and I can see the same file with the bglcomp.exe method. But with GPW, it comes with the dark texture. So, I think GPW does not work well with the PBR material.

 

[arno]

Hi,

The GPW does not change the materials when you process a model, except for the layers.

When I compare your file with the one from the other package, I see that the albedo color property is different. It is 150,150,150 in your file and 255,255,255 in the other one. I think that explains the color difference.

 

[jtanabodee]

I see. I will try that, thanks.

 

[jtanabodee]

Hi Arno, I found something weird.

When I change ground poly to PBR material, the -ve Zbias has less priority than +ve Zbias.

I have made taxilines, put -ve Zbias, they become invisible. I took Zbias-ve asphalt layer and I found my taxiline below it!
When I make +ve Zbias, line became visible over asphalt layer.

 

[arno]

Hi,

I need to check the SDK, but I think you are right. The pbr materials do the layers differently. Now that you say this, I am not sure the GPW is aware of this.

 

[arno]

Yes, the SDK says the decal order is between 1 and 50, so positive.

Using values between 1 and 50, you can set and order the layering of ground polygon textures above the default airport aprons, taxiways and runways.

 

[jtanabodee]

So, ground poly with PBR material needs to be +ve Zbias.
Ground poly with FSX, P3D material needs to be -ve Zbias.
GP with +ve Zbias is higher priority than -ve one.
I found that GPW might move the ground poly to 0 altitude which might cause flickering. It would be nice if you can verify this as well, Arno. Thanks.

 

[arno]

Let me double check if pbr materials are sorted right.

The GPW does indeed project all polygons onto the ground by default. There is a checkbox to disable this in the GPW.

 

[arno]

Hi,

I double checked the code that checks the sign of the layer, but it is already taking PBR materials into account. The PBR materials get a positive layer number.

Which SDK are you using when you export to P3D v4.4 in the GPW?

 

[jtanabodee]

I think it is OK. If I use PBR material and get bgl file, I use MCX to check the value of Zbias in that bgl file. It turns out to be the same as I set in GPW, +ve is still +ve, -ve remains -ve.
But the problem is: there is no cure for flickerning. MCX does put ground poly to zero altitude that cause more flickering.

 

[arno]

Are you using the latest development release? I tested yesterday and the zbias values were updated correctly.

 

[jtanabodee]

Yes, the latest development one. But flickering is still there. I think the problem is not GPW but the ground poly itself. Nothing like FS2002 ground poly, although it has been more than 20 years ago. It is hard to believe that 20 years technology still problem free compare to today's technology.

 

[jtanabodee]

I found that PBR material needs to use with +ve Zbias. If I use -ve Zbias, it will cause flickering.
I am not sure if that is the true statement.