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P3D v4 Trying to get "Fresnel w/Alpha" material going

Hi everyone,

Has anyone had any luck getting the following material to display properly? This has been in the SDK for the longest time, even way back from FSX days, and It has never worked for me. I can't believe that P3D would keep this as a feature through all the versions (1 to 5) without checking if it worked at all.

The material effect is supposed to make edges of objects blend to "invisible". I tried the Fresnel Ramp and Fresnel Alpha as described in the SDK, but the described effect is nowhere to be seen. What am I missing?


Thanks in advance


Resource contributor
Ever since P3D v4.4 and above, Fresnel doesn't work; not needed. Since the use of PBR, it doesn't use Fresnel.
Ever since P3D v4.4 and above, Fresnel doesn't work; not needed. Since the use of PBR, it doesn't use Fresnel.

Thanks - however, P3D is still fully supporting "FSX" material, along with PBR. P3D didn't in any way deprecate "FSX" material.

And again, even before PBR, I have never had any luck getting this material to do what it is advertising...
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Resource contributor
Yes, you are right, P3D v4.5 does support FSX style textures, but doesn't mean that its using the Fresnel texture.

I believe that the fresnel is now handled internally. Per scientific theories, fesnel is based on the properties of the material or texture (based on either specular or PBR Maps). Once it is properly formulated, there isn't a reason to have multiple textures for it.

Is there a fresnel texture within P3D v4.5, either an aircraft or scenery?
Is there a fresnel texture within P3D v4.5, either an aircraft or scenery?
Yes, absolutely - If you check "Aircraft" dir of P3D 4.5, there will be 92 Fresnel bitmaps in that directory alone, either dds or bmp, of varying DXT formats.

And that's just for "Aircraft" SimObjects. So yeah, I'd say there is a lot of stuff still using Fresnel along with the "old" style FSX material.
But are they actually functioning within P3D?
I didn't try those P3D-specific objects, but I have my own objects, and yes, the Fresnel maps are definitely working on my objects inside P3D, as per other modes of Fresnel in P3D SDK. The only one I have the problem with is the last one that has alpha in Fresnel texture.


Resource contributor
So you made it from scratch? What's the size of the fresnel and How are you saving it?
Yes, I made my own. Parameters just like SDK prescribes it: 256x4, DXT5 dds.

Like I said, Diffuse part works as advertised, however, the alpha channel in Fresnel refuses to have any effect.


Resource contributor
That appears to be correct... it must be within alpha channel of the fresnel or you might have placed the transparent end on the wrong side of fresnel.

I'm trying to remember if the fresnel is flipped vertically or not. I can't remember.
I thought of that as well... I have all the permutations of black/white and left/right in my test object. No dice :rolleyes:
I have fresnels working in v 4.5 as an FSX material, together with genuine PBR materials elsewhere, in my C-47 PBR. I am using it for the side views of the propblades, as do most other prop plane designers. The idea is that the side props become invisible when viewed head-on or angled . I do not think PBR can handle that on its own?
Yes, they are alpha'd. I'll see if I can post an MCX screenshot, or maybe an object in max so you can check it in detail.


Resource contributor
If the fresnel is to be fully opaque to transparent, then the alpha should appear white to non existence not black.

A 1m textured cube at 0,0,0. Only the headon side is visible in sim. Includes max source, textures, X, and mdl.

--Old FSX Dog