View-Dependent Displacement

[galagast]

Is there a View-Dependent Displacement setting in Houdini?

Or is it done automatically internally, where farther polygons won't get as much detail?

 

So far, the "Shading Quality" seems to be the only option to control how dense the polygons of the displaced geometry would be at render time.

 

I tried assigning a vm_shadingquality attribute in SOPs, in the hopes to control the quality on a per point/primitive basis to no avail..

 

This came about because I was looking for some other ways to speed up rendering when using displacements with really small details (and high Shading Quality settings).

[davpe]

Mantra > Rendering > Dicing > Geometry Measuring > Raster Space Measuring - this will give you view dependent displacements. Density will be measured in screen pixels instead of scene units (default)

[galagast]

Thanks David. I now played around the three Geometry Measuring options.

 

At first, Raster Space doesn't seem to be working. My buckets were not moving. So I tried lowering down Shading Quality. But still not moving. I even tried doing some combination of adjustments to the object and shaders because it is rendering fine on a simple box using the same shader that I'm using.. But still not rendering.

 

Finally, I tried moving the camera out a bit. Then it rendered!

So I played around a couple of angles to see where the sweet spot is. It's kinda a hit miss. I gave up on it for a bit.

 

Now I switched to Unified Measuring. Bumped up my Shading Quality to compensate for the loss of the detail. For now, it seems to bring me better speeds than Non-Raster.

 

I'll still try and understand why Raster Space is acting weird on my scene.. for now I need render this out

[davpe]

hm, weird... truth is I haven't used this method on many occasions. you can also try to leave measuring method on Non-Raster Measuring and set the Z-importance to zero (on the same tab). that should work very similarly to raster space measuring. actually, later one seems to be the prefered method in houdini 15.

 

houdini help says: 

Raster Space Measuring measures geometry in screen space. This is roughly equivalent to the "nonraster -z 0" measurer, so is deprecated in favor of that approach.

[galagast]

Cool, I'm now using the -z 0 setting for the non-raster. It now gives me the fastest render time among the options.

 

Here are comparison images:

 

Although I've yet to test how it fares on a moving camera fly-by.

 

Thank you again for the insights

Edited February 17, 2016 by galagast

[davpe]

awesome. thanks for testing it out ;-)