Weird glass reflections Trying to make a simple glass but the shading is clearly off (for reference it's similar to IKEA's POKAL glass). To add thickness I didn't use a solidify modifier because the outside geometry is a different shape to the inside so thought this was too much hassle and I just added geometry on the inside manually and joined them. It's a simple lighting setup with just one point light, I tried an hdri but that didn't improve things at all. The only material settings I've changed from default are the roughness (which is all the way at 0 but I've experimented with other values) and the transition (which is 1). All normals are facing the right way and there are no out of place faces/edges/vertices. Changing the number of light bounces doesn't seem to have an effect.
Are you using glass BSDF or transmission of the default principle ? Try to change the IOR value(if it is a glass node). See if that works.
And yes, also check if your model is perfect and a bit high poly. It is not needed but it is recommended.