CoronaDisplacementMod and Bitmap Filter/Blurring

[rs3d]

I read that by design the CoronaDisplacementMod does not react to Bitmap Filter/Blurring to avoid geometry tearing.

Is there any other way to blur the map without resorting to post production? Sometimes a quick way to tone down the displacement detail would be very helpful...

I guess there is no way to introduce a Blur Map, but maybe the modifier itself could offer this option in the future...

[romullus]

I don't know where did you read this, but Corona displacement is respecting filterring and blurring settings in bitmap node. Just tested - it works.

[n2graf]

It dont works with coronabitmap. Only works with 3dsmax bitmap. Not only does it not work with the modifier, it also does not work with the material displacement

[romullus]

Corona bitmap does not have blurring in that sense like it is in photoshop. If you need to blur the map independent on its distance from camera, you must use native bitmap with its blur offset.

[maru]

Could you explain what exactly you are doing and what results you are getting. As you can see in the attached images, if a Corona Bitmap is plugged into the Corona Displacement Modifier, you can adjust its Blur value and interpolation types and this does affect displacement:

[n2graf]

this situation it make the same:

[TomG]

One thing to keep in mind is that the blur seen in the Mat Editor (whether for Corona Bitmap or Bitmap) looks much stronger than it actually is - while the preview may become completely smoothed, if you pop the result into just the Diffuse, you will find quite a lot of detail is still there.

See below - the top bitmap is a sharp bitmap image, with a Blur applied in the Bitmap of 100. In the Mat Editor, it looks completely blurred, but in the render, we can still see a lot of detail. Conversely, the lower image shows the same bitmap blurred in Photoshop, with no blur in the Bitmap. This looks pretty darn sharp in the Mat Editor, but in the render has a lot less detail. So the ME preview can be somewhat misleading in these cases.

[TomG]

For interest, the same connected to the displace and not the diffuse. And results were the same for me with a Corona Bitmap, the Mat Editor is "not to be believed" ;) This will be because the blurring happens over the size of the mat editor preview, vs. over the size of the bitmap in the render (the image is first projected onto whatever size it is occupying in a render in either the preview window or the scene, and then THAT is blurred, not the source image). As you make the mat editor preview larger, more detail begins to be seen, but it's still not large enough to duplicate what is happening in the 3D scene. Meantime, blurring in Photoshop of course happens across the whole source bitmap and isn't dependent on the size of the image inside the rendered area, different sort of blurring altogether. At least, that's my guess :)

[romullus]

Blur vs blur offset in 3ds Max: https://help.autodesk.com/view/3DSMAX/2024/ENU/?guid=GUID-7141A99A-27C3-421B-AF57-1049BDC3FD69

Corona bitmap does not have blur offset, which is what you want to use if you want to have consistent blurring across the image. As i said before, for displacement you want to use blur offset, or better yet just blur the texture in image editing software, you will get much better result that way.

[maru]

To sum up: the blurring and blurring offset available in 3ds Max is not the same as "gaussian blur" in Photoshop and currently we do not have a blur node in the material editor. There is already a feature request for it.

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