rendering speed - mental ray

[john.110848]

any suggestion on reducing the rendering time when interior "ies" light are being use?
we've noticed if only sunlight are being use, the "best" render scene are soooo much faster than if there are also interior lights.

[aspy]

Simplest way to improve render speeds, Dont use Mental Ray

[john.110848]

which other program will you suggest

kerkythea
maxwell
artlantis ( dont look that good?)
???

[rmejia]

IES lights tend to be slower than regular lights, the more lights in the scene the more light bounce calculations have to be made so the slower the render. This is true in any app. Exterior renderings using just the sun will always render much much faster than interiors.

[john.110848]

we already share the same understanding of your post,
but if interior lights are req to render a scene,
and IFFF we have to use mental ray inside revit to render

are there any setting one can share to help on the efficiency
rendering or ways to reduce the rendering time????

[trombe]

we already share the same understanding of your post,
but if interior lights are req to render a scene,
and IFFF we have to use mental ray inside revit to render

are there any setting one can share to help on the efficiency
rendering or ways to reduce the rendering time????

Hi John,


Possible elements on the tick list :
- reduce the FOV
- reduce the depth of the scene
- reduce unnecessary lights
- change intensity of some / selected lights
- re-map IES for alternatives
- ensure mats are as absolutely intended
- ensure colours / colors match required
- reduce/ alter effects in Custom Settings dialogue
- check edits to maps in Render Appearance tab of Materials Properties.


Your post revises and reminds once again, that while mental ray is a fantastic upgrade for Revit over the earlier rendering facility, it is largely an under implemented engine well short of some functionality and speed.
While I am very happy with 2009 and mr relative to RAC 2008 and earlier, and very thankful to have mr now, I am NOT a supporter of the idea that I should have to buy another rendering engine outside of Revit just to access what most other engines have in terms of functionality.
For my work and the costs we pay, I am expecting that mental ray, in RAC 2010, will have more functionality and speed without the need for a huge render farm computer, more shaders and the power to save out mats.

good luck
regards
trombe

[Mike Sealander]

Interestingly, we now do all our rendering in 3dsMax Design. mr is a lot faster in Max than in Revit. Of course, you have to buy Max, but I think it's well worth it. I would rather Revit got better at building design, than have improvements to its internal rendering ability.

[azmz3]

Building design is what the user puts into it, and as long as you know what you are doing, then it is great. Rendering os another issue, while MR in Max is much faster than in Revit, it is because of the way it can use multiple processors for rendering, while Revit cant.

they both do bucket rendering, but Max is able to use more CPU than Revit. You can play with custome settings, which i have done to take a rendering time down to 30 minutes from an hour for an interior rendering with 14 lights, and no sun. I think RAC2010 will have the capability to utilize multiple cores and hyper threading processors and will speed up rendering time immensely.

[sfaust]

slight correction: Mental Ray in Revit can use up to 4 cores to render, so the only way you get more cores from Max is if you have more than 4 cores on your machine. It's only the main interface of Revit that is limited to one core. Max has the advantage of a plethora of settings that you can use to gain speed, as well as the ability to network render.

If you have access to the AU materials, there is a pdf from a rendering class by Jeffrey McGrew that explains what a lot of the settings do and I found that quite helpful to only crank up the settings I needed to for the scene I was doing.

[azmz3]

even with 4 cores in Revit MR, it still only uses 50% of the available processing power. I have a dual-quad core w/hyper threading machine, and i can turn off 4 cores, and it will still only use 50%. but thats true, for modeling/drafting, Revit uses only one core