Bump mapping with gradient bitmaps producing unfiltered results

[suzanne_doherty]

Hello,

I have an odd issue.

In my bump slot I'm loading in a bitmap with a gradient. However when it's rendered it looks like its "unfiltered". I've tried various options within the vraybitmap material, but nothing is helping. I can increase the blur value, which kind of hides the issue, but it's not really a solution.

This happens on various bitmaps, and the bitmaps are high-res.

I'm trying to use bitmaps over procedural, as I need this to work in Vantage too.

Any ideas?

[hermit.crab]

Try baking your gradients to 32-bit EXRs instead of .jpgs (which are 8-bit, which is quite low if you want to match the procedural).

[suzanne_doherty]

Try baking your gradients to 32-bit EXRs instead of .jpgs (which are 8-bit, which is quite low if you want to match the procedural).

Thanks for your reply. These are mainly existing maps that I'd like to use, the radial gradient is just an example. So I can't re-render these.

But it seems like the bitmaps aren't being filtered in anyway. Is this correct?

[hermit.crab]

Thanks for your reply. These are mainly existing maps that I'd like to use, the radial gradient is just an example. So I can't re-render these.

But it seems like the bitmaps aren't being filtered in anyway. Is this correct?

They should be filtered based on the Filtering settings. I presume its their color depth which is the issue. Otherwise, you can easily rerender a Radial gradient ramp by right-clicking on the procedural texture and clicking "Render Map". It takes a second.

[suzanne_doherty]

They should be filtered based on the Filtering settings. I presume its their color depth which is the issue. Otherwise, you can easily rerender a Radial gradient ramp by right-clicking on the procedural texture and clicking "Render Map". It takes a second.

I'm really not sure if the filtering is working as it should. I've swapped to another bitmap, with black and white, no gradient, and you can see the artifacts on the render.

Also, in the Global Switches area, ticking / unticking the Filter Maps doesn't change anything.

[Joelaff]

Those look a lot like jpeg artifacts. Try using a lossless format. 16 bit per channel (48bit) png or exr. JPEG is terrible for line art.

[suzanne_doherty]

Those look a lot like jpeg artifacts. Try using a lossless format. 16 bit per channel (48bit) png or exr. JPEG is terrible for line art.

You are correct, these will be jpg artifacts. However, unless my memory is failing me (which is probably happening!), I thought the filtering on bitmaps was meant to prevent issues like this? At the moment the filtering doesn't appear to do anything.

Yes I agree, re-making the bitmaps in a lossless format would probably help, but that's not always feasible for many projects.

[hermit.crab]

At the moment the filtering doesn't appear to do anything.

In the VRayBitmap node, there's a Filter multiplier - pump it up, and you'll see it works. It's meant to help out by "anti-aliasing" the texture; it can't magically clean low quality maps.