Skip to content

Troubleshooting

Nothing renders, or an object is missing

  • Camera must name a Camera COMP.
  • The object must be in the same network as the Pathtracer and match Geometry / Lights (the default * matches everything there).
  • Its Render flag must be on, and for a PT GEO or PT LIGHT also its Render parameter. A new POP can start with its Render flag off.

Objects lose their texture or shade wrongly

The Pathtracer reads normals (N) and texture coordinates (Tex) from one kind of element for the whole scene: from points, or from vertices. When your inputs differ (some carry them on points, others on vertices), the Pathtracer picks one kind, and the objects that carry the other lose their texture or get wrong, faceted shading. The Pathtracer then shows a warning such as Point attribute N used as but not defined on all inputs. Which kind is picked can change when you add or remove an object, so a new object can suddenly affect another one.

TouchDesigner's POPs differ here: the Sphere POP has point normals and vertex texture coordinates, the Grid POP has both on points, and a PT LIGHT's built-in shapes have both on vertices. The fix is to give every input the same kind. Vertices work for every shape: put an Attribute Convert POP in front of each PT GEO whose geometry has them on points, with Convert Operation set to Point to Vertex, Input Attributes set to N Tex, and Delete Original on. The original point attributes must go, or the Pathtracer may still pick points.

Glass looks dark or black

Light crosses at least two glass surfaces to pass through a glass object (in and out), and more for several objects behind each other. Raise Bounces on the Pathtracer until the glass looks right.

Moving objects smear or leave trails

Turn on Use Velocity on the Pathtracer's Denoising page. With SVGF, also lower Strength or tighten the thresholds under Temporal Accumulation. The Average method is for still scenes and starts over on every change.

Fireflies: single very bright pixels

They come from small, bright light sources seen through rough reflections. Make lights larger, turn on MIS HDRI Map for an HDRI with a sun, trace more Rays Per Pixel, or set Firefly Clamping (see Noise and fireflies).

The scene gets darker or brighter when I resize a light

That is Normalize by Area. On, the light's total output stays the same when you resize it, so a larger light is dimmer per area and a smaller one brighter. Off, Emit is the brightness of the surface, and a larger light gives more light.

DLSS reports that it is not available

  • Check that Plugin Path points to DlssTOP.dll, that you are on Windows with an NVIDIA RTX GPU, and that the graphics driver is current.
  • After a failed start, for example with a wrong Plugin Path, DLSS can keep failing until TouchDesigner is restarted, even when everything is correct again. Restart TouchDesigner before looking further.