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hatrick

PBR masking

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sorry again but i totally stuck with that issue! ....

is it possible to include ore exclude reflections from specific objects with PBR rendering ?...

Please guys ...

If no how can i achive conrolling refl on my objects...

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so .... would just no one use PBR rendering in my case ??

sorry again guys, but i just can not belive that my subject is that hard to solve for someone who knows mantra and it's shading methods...

jason gave me some veryvery usefull tips but i need just a little more support.

i m quite happy with some parts of the rendering but one big problem is the glass!!! it just looks .....?!?!

the thing with the reflections of my white surrounding discussed in a preveous topic, i solved more ore less with phantom objects slightly translated over the ground ore the backgroundsphere with my envmap maped onto.

for me that looks ok for the metalls .... but horrible with the glass... i m shure i make a lot of mistakes with the glass mat but i m on my wits end!! again i would need an option including ore exluding reflections ore light. :angry:

so if someone is interested here are some pics and the hip again.

impala_pokal_v4.hipnc

post-4387-1237735988_thumb.jpg

post-4387-1237735999_thumb.jpg

post-4387-1237736015_thumb.jpg

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my problem with raytrace and micropolygon is that the rendertime gets absolutly not exaptable....

may i need to tweak my overall settings to go with micropolygon rendering but where i should begin to tweak ?

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I think that one major problem with the glass parts in your scene is that they aren't double sided, which means that they don't have a thickness and will always look funny (the light bulb on top for example looks like a glass ball, not like a bulb that consists of a thin glass wall and lots of vacuum inside - that is because your geometry doesn't have "walls", its just a volume of glass from one side to the other). Try using the peak SOP to create inner walls and reversing the normals on them, then merging the result of that with the current glass geometry. This will make refractions much more appealing.

About PBR: the way it is in H9.5, you have to approach it thinking more like a photographer than a CG artist. As a photographer you have certain physical contraints of what part of your setup will show up as a reflection/refraction etc - the same applies to PBR in H9.5. It may be too much of a complicated task ATM - specially since I'm not actually sure what style you are going for. I would recommend staying with micropoly/raytracing for now, this way you can use the masking options and fake your way towards a pleasing image.

As for rendering speed, you should be able to tweak the amount of raytracing bounces on the glass/metal materials to reduce render time. Also, tips like this and others ( like this for example) might help further.

cheers,

Abdelkareem

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hi,

in my last version i ve used the polyexrude SOP and normal reverse for my glas parts and their thickness .... the result was not that good....

but thx for your tips

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could someone please check the orientation of my normals of the 3 glasobjects....

i m not completly shure bout that because the reverse sop does not take any effekt in the viewer....

i think its ok after subdivision of mantra....

thx

impala_pokal_v5.hipnc

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The orientation is correct, but I think you made the glass objects much too thin (except for light bulb which seems about right). The thickness will of course have a big impact on the look of the glass. You can toggle on primitive normals in the viewport, and change their length to see better.

post-37-1237754085_thumb.png

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hey...

finally i figured out a glassetting which makes my bulb look right i can not beleave how sensitive the meterial reacts... additionally i did some tweaks in the surrounding setup and it looks i can stay with PBR :rolleyes:

i thought that the bottle and the other glass object are to thick... i ll try the other way round..!

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are not the point normals used for shading ? cause you ve pointed on the facenormals ...

:) Paulaner Hefe Weizen.... i d love a houdiniwise nativ german contact ....Austria here

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could someone tell me something about PBR rendering and ambient occlusion.. i mean shadowocclusion

thx

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Point normals are used for shading, but unless you're manipulating them you don't really need to think about it. If your polygons are facing the wrong way though, you're gonna have problems with shading. For occlusion, try the environment light (from the shelf). And sorry, my German is very rusty, though I still love the beer. :lol:

post-37-1237762800_thumb.jpg

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one little step closer with the help of you guys and hours of trying around....

i stayed with PBR rendering

post-4387-1237802912_thumb.jpg

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when it comes to texturing....

if i lay a texture on a lowpolymodel.... ho can i stick that texture when mantra subdivides while rendering. so that the position is interpolated correctly?

Do i have to subdivide and texture afterwards ?

thx

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when it comes to texturing....

if i lay a texture on a lowpolymodel.... ho can i stick that texture when mantra subdivides while rendering. so that the position is interpolated correctly?

Do i have to subdivide and texture afterwards ?

thx

The texture coordinates should be subdivided correctly if you texture first. Also, you might want Mantra to subdivide for you, instead of using the Subdivide SOP and creating polys. Leave your geometry as the subd cage and switch on "Render Polygons As Subdivision Surface" on your Object's properties.

Jason.

PS. If you space+5 in the Viewport when in SOPs, you'll see the UVs of your object. See how the Subdivide SOP works ok before and after the UV projection.

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thank you!

i got close to the end .....

Nice!

I have a sneaking suspicion that your Index Of Refraction (on your glass "arms") is inverted from what it should be. Is it 1.5 or so? The Material in Houdini really wants an inverted value for that (1/1.5 -- I actually hate this fact, I wish they'd just use the regular, well-know IOR values.)

Also, your flask: it's shading as if it's solid glass. Is your glass thickness smaller than your ray bias?

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:) interesting questions jason :)

i ll check that .... i use the same glassshader on all glass objects

Edited by hatrick

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