Houdini does this when I apply glass material or change the opacity parameter of another material, and use a shading mode other than wireframe or bounding box. I'm using Houdini 16 and a Intel HD 530 GPU. Updated drivers, uninstalled and reinstalled Houdini but nothing changed.



Rendering still kinda works though but it looks much grainier than usual.



Any help would be appreciated !

That looks like quite a spectacular driver bug. I'd try changing the Transparency quality to Low first (Display options, Effects tab), and if that doesn't fix it, turn Transparency off altogether.

The noise in your render is coming from rough reflections. Try turning the reflect limit down to 0 for the objects with rough (metallic) reflections. The windshield also looks like it has refractions on, which requires the interior to sample through the glass to the light source, which is effectively a caustic light path and very hard to resolve. You can optimize this by disabling refraction on the window, and making it non-opaque. If you must have it bend the light, disable the refract contribution on your light source, and enable fake caustics on the refractive material to allow light to pass through (by reducing opacity for shadows), preventing the need to compute brute force noisy caustics.

That did it, thank you ! Btw I also semi-fixed the grain simply by increasing the pixel sampling