Hair&Fur crashes in combination with PointCache?

[S-P-A]

Hi everybody!

Straight to the problem:
I'm currently doing a character-setup with Max2010-64bit and in my scene file there are only 2 vray-lights (set to sphere), a simple irradiance-bruteforce-gi illumination and a character-model which uses one multi-sub-material (ID1 for skin with the new sss2-shader, ID3 for eyes ,ID8 for the jacket, and so on)
The character itself consists of 20 seperated parts (head, eyes, jacket, trousers, shoes, etc.) and each part is not skinned but has its own point-cache-modifier and uses a test-animation as source which is originally cached from the skinned version. (We want to keep the animation- and rendering-parts as seperated as possible, so you dont have to re-merge a character again into the final environment once the animation gets changed.)

This all works fine up to the point I activate Hair&Fur (using the "mr prim" option) on one of the objects (e.g. the face has a beard, the jacket some extra fur-edges, etc)
From this moment on, only Frame 0 renders correctly, but all following frames more or less tend to produce errors. Mostly the famous "UNHANDLED EXCEPTION:Irradiance map thread" message. Most times with an instant-killing of Max.

I get no crash once I:
- deactivate all pointcache-modifiers, or
- deactivate all Hair&Fur-modifiers

Now comes the really odd thing: before the crash occurs, I clearly can see that some objects are rendered in a distorted way or at the wrong place. But this ONLY happens when the hair is activated.

Currently I suspect that somehow there is some kind of memory overload once V-Ray adds the Hair&Fur to the rest of the scene. Because some of the animation frames have these distorted meshes (point-cache gets interpreted the wrong way?) or objects are completely black and only show a specular layer (bitmaps can't be used anymore?)
BTW: the bitmap load is quite heavy. The guy uses about 8 bitmaps, each 4096x4096.

Things I tried till now:
- switching between PC2 and XML: no effect
- turning off all lights and shadow calculation: no effect
- turning off everything that does pre-calculations, e.g. Irradiancemaps and SSS2: crashes also, but now with a simple "Unhandled exception"
- only having hair on static/non-precached objects: no effect
UPDATE:
- giving everything one grey V-Ray-Material: no effect, still crashes

Now I'm running out of ideas where to look. We are burning to use the new Hair&Fur capabilities of V-Ray SP3a and swiching the whole pipeline back to non-point-cache would be a huge pain.

So, someone got any idea what this could be?

Many thanks in advance!!

[vlado]

Do you have a scene for this?

Best regards,
Vlado

[S-P-A]

Hi Vlado,

I'm currently trying to replicate it into a test-scene cause the character subjects to an NDA-condition ...or at least to break it down into not-so-many objects and pointcaches.

Will post again as soon as there is something to download.

Thanks and best regards,

[S-P-A]

Good Morning!

Finally it was possible to recreate the whole thing in a much simpler scene.

The attached file contains the characters head and some simple but poly-heavy cylinders to simulate the workload. All of these objects have an animated bend modifier so the pointcache has something to eat. All you have to do is to re-record the pointcaches onto your harddisk. That head also has a simple Hair&Fur-WSM, right out of the box with default settings.
(The scene file starts with frame 3 because the effect kicks in after frame 0)

I illustrated the vicible impact in those 4 pictures.

As you can see, in pic1 with no hair activated, there is simply a row of cylinders and a human head, each bend by the pointcache.

In pic2, the hair count is only 15, but there is already a cylinder gone in the row. In the viewport, it is still there.

In pic3, the hair count was around 1500, more cylinders go into oblivion.

In pic4, the hair count is over 15000, even more objects are gone, and one more thing happens, which I called the "distortion" in my previous post: the head gets somehow duplicated to the bottom. (On TFTs you maybe have to look closer because the duplicate is in shadows, right in the middle of the picture in the gap between the cylinders)
In the original character file, this also happens to various other objects, which aren't directly involved in the hair setup, eg. hands and shoes, are not moved by duplicated down somewhere at floor-height. This also randomly changes, so e.g. rendering the same frame twice creates no error at all, or a new duplicate, or different positions or a complete crash.

I'm currently hoping and guessing this all goes back to a problem directly connected to the head-mesh and not the hair-calculation in general. Should be, because once I kick the head out and add the hair onto one of those cylinders instead, no problem occurs.

Oops...update: The zip-file of the testscene is still around 1MB and so I cannot attach it. Please drop me a private-message with an email-address in case anybody wants to take a direct look at it

Thanks again!

[S-P-A]

Good Morning again!

Here comes an even simpler version of the test... small enough so it is attachable.
Just open the maxfile and assign a standart Hair&Fur-WSM to the sphere.
Now render it at frame 3... the bend cylinders are gone. As soon as hair is switched off, they are back again.

The interesting thing is: there is not any pointcache modifier in that scene anymore. Just a sphere and some bend, instanced cylinders.

Hope this helps to get closer to the actual trigger of the problem.

...any now it's time for some coffee

[Paul Oblomov]

I turned off bend modifier - and it all works again

Also - convert your sphere to editable poly - and voilla - IT WORKS!

[S-P-A]

I turned off bend modifier - and it all works again

...yupp...that's the strange thing about it all. Seems like Hair&Fur doesn't like vertex-animated stuff. Really strange.

Maybe I just have to convince my boss that stiff characters look way cooler in our cutscene and they have to rewrite the storyboard so that there are manikins running ...errrrr sliding around

Also - convert your sphere to editable poly - and voilla - IT WORKS!

Hmmm. That sounds really interesting. Will give it a try asap.

[S-P-A]

@Paul:

That Tip about the polymesh is pure gold!
Looks like Hair&Fur combined with V-ray only accepts meshanimations when they come in the costume of a poly, not when being a simple editable mesh.
I tried it on the first test-scene I posted above, the one with the head.
As soon as the cylinders are set to Editable poly, the stop disappearing.
As soon as the head is converted to poly, it stops duplicating.

Wonderful! Will try it now on the original character setup.

[Paul Oblomov]

Hehe. You owe me a drink

[S-P-A]

YES! That worked!

So to sum up for everybody else: when using skinned/morphed/pointcached/somehow-else-vertex-modified objects in conjunction with Hair&Fur: stay with EditablePolys and not EditableMeshes.

(I wonder if this is a better way for V-Ray renderings in general?!)

@Paul:
Thanks again!
Yupp, I owe you a drink! Will bring it with me as soon as I am visiting the dark side of the moon again