Actually, I don't believe there is ever any creation without intention.

At the most fundamental level, everything in your life is based on an intention. You are on InwardQuest reading this answer right now because you intended to... you took a breath a few seconds ago because you intended to... you are living right now because you intended to :)

(I should also add that trivial things like breathing and living are creation as well... it's just that you are creating the same thing again and again from moment to moment)

With that in mind, let's look at the example you gave at the start of your question...

I came across this idea that intentions are good but lets say you want to do something creative, a work of art, a meal, detailing a car ect.. beyond a fixed outcome in mind.

For example you let the universe decide the outcome, you don't set the intention, you just get to work and focus.

In this case, the intention would be wanting or deciding to do something creative... wanting to paint a painting or wanting to cook a meal.

Because we know now that everything is an intention... the essential difference between just "wanting to paint a painting" and "wanting to paint a painting of a specific image in a specific style with certain specific colors" ...is simply the specificity of the intention.

The first intention is less specific and the second intention is more specific.

And that's essentially what your question comes down to... is it better to be less specific or more specific?

The answer?

It's all up to you and how you want to live your life :)

The only intention you need to get everything you would ever want is the intention to get happy.

However, as the previously linked answer mentions, you'll find that getting specific can often be quite fun, since it gives you the hands in the clay feeling of molding your life the way you'd like it to be.

But getting specific is entirely OPTIONAL.

In case you're wondering what I do... I usually like to play with my creations in one of two ways:

1. Get as specific as I possibly can (by writing a list of what I want and why I want it, writing a letter, creative visualization etc.) as long as the specificity feels good. I then take any inspired actions that come to me.
2. Purely follow my inspirations and let the universe surprise me.

There's no right or wrong answer here... you can be as specific or general as you want to be. You'll find that you want to be more specific at certain times, and less specific at other times... you'll also want to be more specific with certain creations and less specific with others. Whatever you are most excited about doing will be right for you... it's all there for your joy anyways :)

However, there is one very important thing I want to mention, and I find that this trips up a lot of people when they get specific. Only get specific for the joy of getting specific, and not to insist on things coming about a certain way.

You lightly touched on this in your question...

I know we create our own realities but I'm wondering if it's just as good or if not better to remain open to the outcome of the universe.

It is always better to remain open to the outcome of the universe!

You do this "by default" when your intentions are very general... but what I'm trying to communicate is that you should do this even if you have specific intentions!

One thing I love hearing Bashar say is: your physical mind's intention / vision is the highest / best end result that your physical imagination can conjure... and that same intention / vision is the lowest end result the universe (your non-physical imagination, so to speak) will conjure as a response.

In other words, your specific intentions and visualizations are the worst possible outcomes. :)

If you let go of insistence on things happening in a particular fashion and you let the universe take care of the physical details while you stay in the vibration of the state of being of your specific intention (i.e. what it feels like to live that intention), the universe will respond to you with something that is at least as good (but likely better, possibly with other manifestations blended in) than what you had originally intended. What could be better than that? :)

And everything I just said to you in this answer is embodied in one metaphysical paradigm:

Follow your highest excitement to the best of your ability with ZERO insistence or expectations.

EDIT

I noticed I got very general towards the end of my answer and digressed from what you were specifically asking, so I thought I might close with a concrete example that illustrates what I said above.

Let's say you feel inspired to paint a painting, and you decide to follow that inspiration without any attachment to what the outcome should be (i.e. "without intention"). While painting, you get a text message from your friend who is asking if you'd like to meet up for lunch.

You immediately lose your enthusiasm to complete your painting and excitingly agree to go have lunch. While having lunch, you mention that you were working on a painting and your friend tells you she won free tickets to the local art museum. The two of you decide to go to the museum after lunch. At the museum, you see amazing works of art which invigorate your imagination, and after returning home, you jump right back to your painting and proceed to create a colorful masterpiece that leaves you breathless!

Now let's take the other route. Let's say you feel like painting a painting, and you set the intention to create a colorful masterpiece. As you're painting, you get a text message from your friend about lunch... but wait! You're in the middle of creating a colorful masterpiece and you aren't going to leave your easel until you see one! So you tell your friend you aren't interested in lunch, even though you felt enormous enthusiasm for it.

You're no longer inspired to paint, but you want that masterpiece! So you spend a few more hours forcing yourself to paint until you finish off with a colorful master-mess that leaves you breathless out of frustration :)

However, if you listened to @WeRadiateBeauty and didn't insist that the colorful masterpiece come to you in a certain way, you would've gotten it in the best way possible (like you did in the first scenario!). So nothing wrong with setting intentions, just don't insist :)

In the end, there really is no difference between setting / not-setting intentions since your colorful masterpiece was (vibrationally) created the moment you wanted it. Not setting an intention gives you a delightful surprise of a colorful masterpiece, whereas setting an intention gives you the satisfaction of being a deliberate creator.

There's no right or wrong; you'll find yourself drawn to one or the other.

And as I said before, setting an intention is completely optional... if you are setting an intention from inside your Vortex (i.e. in full alignment with your Inner Being) you're likely setting an intention for something that is going to happen anyways (just like in the example).

Remember, there is no "out there," everything is inside you. So, letting the universe decide the outcome, is essentially just letting yourself decide the outcome, because the Universe / Inner Being is You, just the part of you that has a broader view.

Hope you found all that rambling useful :)