Cineversity

Hi Doc -

I hope you’re well, my friend!

I’m working on adding grass to an object (a book) that will be rendered as a still image, and have 2 questions…

1) What is the easiest way to isolate the grass to very specific parts of the book object?  For instance, I’m trying to make it appear as though the grass is growing out of gaps between pages and from the edges of the book cover.  I’m guessing that this will have something to do with a vertex map.  If it does, please keep in mind that I’m a vertex rookie. 

2) Will I need to use a Hair Object rather than the Grow Grass feature in order to have the grass interact with dynamics?  As far as I can tell, the answer to this question is yes, but thought I’d ask the expert.

I’ve attached a screen grab showing a nice grass effect where the grass grows only from specific areas.

Thank you for your guidance, Doc!

Mark

Hi Mark,

Do you need an upload link?

Edit: link send. Yes, I’m doing fine, and just finished watching a movie, so I’m in the Long-Weekend mood. I hope you had a nice one as well /edit

Cheers

Thanks.  I shouldn’t need an upload link.  For some reason, when I attach the 369 KB JPEG file, it’s not attaching.  Odd.  Perhaps I do need an upload link.  Hmmm.

Too large? 800x600 max.

edit: yes, way too large, and:
Ps Alert:The embedded ICC profile cannot be used because the ICC profile version is not supported.  Ignoring the profile.
/edit.

Yep.  It was too large.  Here’s a smaller grab.

Thanks, Mark, for the upload.

I assume the gap between the pages, is based on that the book is not entirely closed? Hence why a scene file is always better, this Image sows me Grass in gaps, but not really what you see in it nor what the target is.
My impression is, since it is a still, and relatively very little Grass, that the Hair options are much better to art-direct the results. I would go perhaps even so far to set up polygons (invisible) for these areas in question, so you avoid the preparation of the book-pages itself.

The first one that came to my memory is this one
https://www.cineversity.com/vidplaytut/special_effects_adding_grass
A newer one is here
https://www.cineversity.com/vidplaytut/victorian_house_set_extension_with_projection_man_grass_picket_fence

There are more tutorials, but why to copy a list while the search term Grass is undoubtedly something you have used, I assume.

I will explore the options and share a file or two.

Talk to you later.

Mark,

Here is a screen capture with hair, and the scene file created while recording. Another file shows the Grass Shader with a Gradient Shader.
https://www.amazon.com/clouddrive/share/gl1dPj2g2o7mzNuWBFmwo8bUpS2FRIwUNaISK0frG5v

I guess the Hair object is the way to go. The scale was not clear to me, perhaps it needs to be smaller, and more of them. Besides using the spline as a base, the before mentioning invisible polygon is probably a more precise way to go.

Let me know what you like to have, or perhaps how close the examples were (or not close at all)
I will have a look in the morning into it.

Here is another little screen capture and a file, it is brainstorming about the Grass shader. The Grass Shader might be supportive to get the coverage on the floor (going by your image).
https://www.amazon.com/clouddrive/share/nNCiHitvdUetFkli2G81ejdj5SJWDqQ9f9p2M07uxIG

Enjoy.

Good morning, Doc.  I haven’t explored the options above yet, but I’ll send you my scene file right now, just in case it helps to have it.

Good Morning, Mark.

Thanks for the file, this makes so much more sense now.

Here is a file (sketch) that you can ‘Merge’ to your scene, the position is taken from the book.
https://www.amazon.com/clouddrive/share/nm2uYGEINY8FJM8MKw5BzoidXI1iu6geO5dPMJ8U4S5
If Hair was not enabled, then please switch it on.

Alternatives
https://www.amazon.com/clouddrive/share/vq9wfgjGmBl1ksshpvR96Z2iUmYmk3Eo1drOv1qUQBm
Or this one with three Grass Shaders, less interactive compared to Hair, but perhaps worth a try. (Image below)
https://www.amazon.com/clouddrive/share/L1iLcCzHblyg8ptBqH0swxIYEAYhEdK5tyj7UTHE0tz

All the best

Brilliant, Doc!  After about an hour of playing around with your scene merged into my scene, I’m getting just the look I want.  Thank you so much for your help with this!

You’re very welcome, Mark, thanks for the feedback!

Let me know if there is anything else, I’m happy to look into it.

ENJOY