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Andrew West

Reflections

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Is it possible to ACCURATELY place a reflection in the windows of a building?  In form.z I would place a vertical plane behind the camera and set its reflectance to constant and shadow casting/receiving off.  If I try this in Maxwell the only way to get the plane to not cast a shadow is if I set its attributes to "hide from camera" which then hides it from the reflection.  In Maxwell it seems that the only way to get a window reflection is to create an IBL light and load an image into the reflectance channel which produces a random refection with no control over where it sits on the glass.   Does anyone have a trick for this?  In essence I need a certain mountain peak reflected in a certain window area of a building. 

Thanks

AW

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What about texture mapping a semi transparent image right onto the glass?  Tricky though if the windows are at different angles, maybe a texture group assigned to all panes facing the same direction?  At least this way you could preview the success of the effect in OGL.

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Not sure how I would go about that and it still seems somewhat random.   In Form.z when I create a reflection plane behind the camera I move the plane or texture around until I get the reflection exactly as I want it.  Usually takes me three or four quick test renders in about 15 minutes which is fantastic.  I can not over emphasize how important the accurate reflection is to both the composition and the marketability.    

What is OGL?  

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Hi Andrew,

 

This should be achievable, but I need a finish rendering example to show what you are looking for. Can you please post an image, or a link to an image, of what the final result should look like? I need an idea of how reflective the glass is and how much of the interior is visible.

 

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Hi Andrew,

 

(Before you posted those images, we found an image of yours in the formZ gallery and used that as a reference while working. It's not quite the same as what you posted after we made our example project.)

 

We reworked your setup as follows.

 

MODEL:

• Added columns inside the space, so you can evaluate transmission as well as reflection.

GLASS:
• Use the "Architectural Glass, Normal" material hint, with Shaded transparency set to around 50% for greater reflectivity. You will want to experiment with this value.
• When using Architectural Glass (i.e., AGS, rather than true "High Grade" glass), your glazing should be modeled as a single surface, not solid objects. We corrected this.
• Enable "Hide Architectural Glass Hint Materials from GI" for efficiency. (If using a referenced MXM AGS, do this manually by enabling 'Hide from GI' Maxwell Attribute on each glass object.) We enabled this.

IMAGE TEXTURE:
• The plane material must be made an emitter- like a giant photo lightbox. See setup for "Background Plane Emitter" material.
• There were multiple dot (".") characters in your image map filename. While this will work most of the time, it can cause issues over networks, on renderfarms, etc. Replaced with dashes.
• We are going to use an image emitter material in the plugin, so it needs to be in an HDRI format. To convert your image, follow the steps below.
    1. In Photoshop, open WilsonPeak-Telluride-CO-Photo-Credit-The-Hotel-Telluride-HiRes.jpg
    2. Select Image > Mode > 32 bits/channel (or equivalent in your version)
    3. Select File > Save As..., and set the format to Radiance (.hdr)

• Make sure the normal of the mapped plane faces the subject; emitters only emit light in the direction of the normal.

CAMERA:
• Closed aperture to f22 for extreme depth of field (fine for architecture, and renders faster)
• Adjusted exposure

RENDER SETTINGS:
• SL set to 12
• We created an Extra Sampling channel for just the glass material, and set it to render to SL 15

• Enable Multilight. This allows you to adjust the intensity of the background image after rendering.

• Disabled Reflective Caustics and Refractive Caustics for efficiency

 

This 1200x900 rendering took 6m 55s on a machine with geekbench score of around 16000, with multilight enabled.

 

post-32-0-04286800-1459443707_thumb.png

 

post-32-0-47501800-1459443738_thumb.png

 

PROJECT FILE:

Requires latest Maxwell Beta: http://forums.formz.com/index.php?/topic/3601-new-maxwell-for-formz-early-build-3208/

 

Glass_Test_Fixed.zip

 

 

 

 

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Here's one with the glass material transparency set to 25%.

 

5m 20s with multilight disabled in this case.

 

post-32-0-03997300-1459444969_thumb.png

 

Obviously this is just a proof of concept; in the real context with the entourage and so forth, it will look much better.

 

 

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This is everything that I could have wished for in one place!  For what its worth this should be used as a tutorial somewhere where it can be easily found.  Anyone involved in architecture would benefit from it tremendously.

 

One thing that confused me is the change from solid glass planes to single planes.  Form.z Renderzone does not like single plane glass and renders them poorly. 

Edited by Andrew West

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Andrew,

 

Good to hear. Honestly, it was the project file that you posted that allowed me to figure out what you were after. Project files are worth (more than) 1000 words...

 

For true glass with refraction and caustics, model the glass as a solid volume, and use a true glass material such as the plugin provided "High Grade Glass" hint. This would be appropriate for glassware, for example. However, at architectural scale, those phenomena are usually barely perceptible, so it's fine to use the AGS cheat that will render faster: planar surface objects assigned the plugin provided "High Grade Normal" hint.

 

Please let us know if applying these best practices resolves the issue you were having with longer render times.

 

 

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My render time on the current project dropped from 37 hours to just 3.  You have just saved me thousands of dollars in Render Farm services. 

 

On a separate note there is a very minor issue with the Maxwell Attributes tab.  If I select an object and hit Attributes then select Maxwell Attributes I can change the settings.  If I then select another object and go to Maxwell Attributes the window is blank.  Nothing to select.  I then go back to Renderzone or Shaded attributes for a second and then go back to Maxwell Attributes and then the options show up.  A minor issue but one worth noting.

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Upon further tweaking of the materials (reducing ambient to 95%) and render settings using your guide lines above I was able to reduce my render times from 37 hours to 1 hour and 11 minutes.  Never thought I could get it that low.

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Andrew,

 

Good to hear. In exchange for those thousands of dollars saved, I would ask one thing: Could you please go back to the few other threads you've contributed to recently about exceedingly long Maxwell render times, and mention that you have resolved the issue-- sped up your renderings 31-fold-- by observing best practices.  Perhaps you could link back to this thread? It may help others. I want others to know that Maxwell can indeed be used in a production environment.  Thank you.

 

Whenever you have issues, please send a project file. I could have sorted this out for you a year ago if I had a project to work with.

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Also, use the new "Fast" material hint instead of "Realistic Match" when possible.  It is similar to "Realistic Match," but somewhat more efficient.

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Just wanted to piggyback on Evan's post above, if I may. Yes, thank you Ben for being a wonderful resource to the FormZ and Maxwell community. Your responses are very helpful.

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Ben

I am having trouble again with the reflections in the windows of a building.  I have used the same settings as you used in the demo above but nothing is showing up in the glass.  Here is a link to the dropbox file which contains everything. https://www.dropbox.com/sh/njjheirnpm3f23y/AAD8BdbHc9cFJFJJPHd-4l2ga?dl=0    If you could take a look at this and let me know what I am doing wrong that would be very helpful.

Thanks

Andrew

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Hi Andrew,

 

Thanks for sending your file.

 

An an emitter object only emits light in the direction if the face normals, so with a surface object, you need to make sure it's pointed in the right direction. If you 'show normals' on your emitter object, you'll see that they are pointing away from the building. Use the 'reverse' tool on the object and you'll be good to go. (Rendering looks great, by the way.) I edited the instructions in my previous post to include that detail.

 

post-32-0-24834800-1459971649_thumb.png

 

I also noticed that your windows are 5 sided "open" cubes (the front faces have been removed). Instead of deleting the front face of each pane of solid glass, I would recommend using the 'Derive Face' tool with the delete option enabled (and click on the front of each pane) to convert your 3D solid panes to a single surface each. I don't know leaving them as they are will affect efficiency, but since it's so easy to do it the proper way, why tempt fate?

 

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Ah ha!  I knew it had to be something obvious.  As for the derive face tool I have never used it so I just did it the down and dirty way.  Learned something new today. Thanks.

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A new problem has cropped up that I could use some help with.  I am working on a project where the entry is shot in daylight and the back of the building is an evening shot.  I find that the glass is perfect for daytime reflections but it looks too reflective at night.  What I did to get around this is to select and copy the glass onto a new layer called Night Glass.  Then I created a new glass material for night time.  One thing that still gets me is that I need to change my camera settings for each lighting situation.  I copy down my Maxwell camera settings in a notebook for reference as I change them back and forth.  Is it possible to create  camera settings for each scene and save them within the file? 

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Hi Andrew,

 

You can definitely store different camera settings for various lighting situations. An pencil and paper are not necessary. There are two approaches:

 

1. Have more than one window in your project. Each will have its own set of render options, including camera settings. This approach is okay for quick one-off tests, but doesn't scale well, plus, you might accidentally close a window.

 

2. A better solution is to keep a single window, and use formZ Scenes with the "Rendering Parameters" option enabled:

post-32-0-21151400-1461153629_thumb.png

You can select any other relevant options there, too.

 

Note: You need to remember that formZ Scenes are "active" when created, so any changes made while the red bullet is on will be saved in the scene. This is the opposite of how Views are handled, and can lead to some confusion if you haven't used Scenes before.

 

In Render Options > File, you can see that the Scene name will be added to the output Maxwell filenames by default, but you can turn this off if you like:

post-32-0-93653200-1461154021_thumb.png

 

 

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Thanks for the solution.  I closed down the scene palette (along with many others) a year ago to clean up the mess of palettes all over my screens.  Looks like it is going to be very useful for my multiple lighting situations.  Hopefully the future releases will tidy up the interface issue. 

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A very welcome addition would be to save various different render settings within the file and externally, such that they can be reloaded at will. I gave up trying to use the scene palette, as it's too confusing.

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