Creating displaced geo for bump?

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Is it really necessary for Mantra to create displaced geometry when the `Bump Only` tickbox is on in the displace along normal node, when building my own shader?

I am working with a really high res geometry and this adds allot of time to the render. I just need a fine turbulent noise as bump on the surface.
Werner Ziemerink
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No, you need to not have a displacement shader though. The default ‘wrapper’ material will include a displacement shader if you don't actually have one, unless the terminal node is one that explicitly doesn't such as a collect vop with only surface input. To indicate force no displacement shader, add the material property “shop_disable_displace_shader”, and flag it on.
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Thanks jsmack, but I must be doing something wrong.

I've added the material property, but when I tick it on, the bump does not work at all.

hip included.
Edited by Werner Ziemerink - Dec. 1, 2017 13:13:57

Attachments:
bump_error.jpg (113.2 KB)
Bump_displace_Problem.hip (441.1 KB)

Werner Ziemerink
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The same thing happens with the Principle and Classic shader. Heavy meshes with noise bump maps will bring the render to a grinding halt before it even begins. Bump maps should be quick.

The same image takes 0:00:05 to render without bump.
Edited by Werner Ziemerink - Dec. 1, 2017 16:42:54

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bump.jpg (141.9 KB)

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The only way I could get it to work without long upfront geometry calculations…if someone else falls into the same trap.

Attachments:
bump.hipnc (371.2 KB)

Werner Ziemerink
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oh, you are doing bump with a displacement shader. Add the render property vm_truedisplace, that'll do ya.
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Thank you Sir! That is what I was looking for. Very helpful.

Enjoy your weekend.
Werner Ziemerink
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I am having this problem with packed geometry and H16 sometimes it start to create displaced geometry without any maps, anyone else having this issue? Any tips please?


Thanks.
http://www.vimeo.com/17790588 [vimeo.com]
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Make sure you aren't applying a displacement shader. If you apply a ‘bare vop’ as a material, it will automatically create an empty displacement shader, which can lead to that problem. To force NO displacement shader, you can use the render property ‘shop_disable_displace_shader’. If you were relying on a displacement shader to do bump, note that this will disable that as well. If you displacement shader only performs bump, be sure the use the render property ‘vm_truedisplace’ with it set to False.
Edited by jsmack - Dec. 7, 2017 16:11:30
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Thanks for the feedback, here what I am doing and I noticed a strange behavior in Houdini.

If I use a classic shader and collapse it on a material shader builder because I want more stuff inside it automatically starts to create displacement geo on my packed objects that shouldn't happen right? I didn't test on non packed geometry.

Any tips besides change to Principled shader?

I am using 16.0 build 736.
Edited by mzigaib - Dec. 7, 2017 21:06:57
http://www.vimeo.com/17790588 [vimeo.com]
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It doesn't matter which shader you use inside the material builder. Either disconnect the displacement wire, or make sure the render properties from the classic and principled shader are transferred to the properties node created when collapsing. Currently only the displace bound property is automatically transferred, but you will need the “shop_disable_displace_shader” property that is invisible on the classic and principled shaders if you want your new material to behave the same with displacement inactive.
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Thanks again for the feedback.

Disconnecting the wires didn't work it still insists in displace the geometry, I'll try the property next.
http://www.vimeo.com/17790588 [vimeo.com]
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