VRayBitmap vs Bitmap render speed

[dimitar_panayotov]

Did you try to reset the render settings? Maybe the old scene was prepared in a different way. So resetting the settings will give a good clear start.

[DCHA34]

Did you try to reset the render settings? Maybe the old scene was prepared in a different way. So resetting the settings will give a good clear start.

After rendering settings reset :

3DS MAX 2024 + VRay 6 :
- 6m39s instead of 4m46s
- 5m56s instead of 6m15s

3DS MAX 2025 + VRay 7 : idem above

I thought the results would be much better with the default settings of VRay 6 or VRay 7.
Not so. An old file from 3 years ago gives better results (4min46s) in terms of rendering time for the same quality.

[dimitar_panayotov]

When you removed the window lights, that were used previously for portals, did you add an adaptive dome light?

[DCHA34]

No, I just left the VRay Sun.

[Vizioen]

No, I just left the VRay Sun.

Try and put the VraySky map in the domelight set to adaptive and remove it from your environment. Also without any RAW output examples and noiselevel renderelements, rendertimes don't really mean anything.

[DCHA34]

Try and put the VraySky map in the domelight set to adaptive and remove it from your environment. Also without any RAW output examples and noiselevel renderelements, rendertimes don't really mean anything.

5m58s with your workflow. Still longer than the 4m46s render time with the Skylights.

[^Lele^]

On bitmap speeds: it's wholly expected, as the default v-ray bitmap filtering is a lot sharper than the max bitmap.
The better visual quality also means higher sampling will be needed.
You can testrender both your variants adding a samplerate RE. you'll see the added sampling is at grazing angles, where the vraybitmap loader's filtering provides for good data, compared to the blurrier one of the max bitmap's.
The more grazing angles in a given shot, and the higher the resolution, the higher the sampling, the more the effect will be pronounced.
Switch to isotropic instead of the sharper version, and the filtered results and rendertimes will be closer to the Max's loader.
"slower" or "quicker" are meaningless terms unless the results of the computation is taken into account.

On interiors and portals (and as a general lighting setup rule): you'll want your sky/gi environment away from the background (we don't importance sample that, like corona.) and into a dome light, which by default is set to adaptive.
The adaptive dome supplants old portals.
A number of old hacks will produce slower and noisier renders today, scene setups of old will have to be reworked.

below, a contact sheet of the three loaders, their sample rate REs in the second column, and the difference between these (mulitplied by 10, for clarity) in the third.